Ebook Essential clinical anatomy (5th edition): Part 2

(BQ) Part 2 book Essential clinical anatomy presents the following contents: Surface anatomy of lower limb bones, medical imaging of lower limb, surface anatomy of upper limb bones, surface anatomy of arm and cubital fossa, surface anatomy of forearm and hand, surface anatomy of cervical regions and triangles of neck, surface anatomy of larynx,...

309

Anatomical variations

BONES OF LOWER LIMB 311

Hip Bone 311

Femur 311

Patella 315

Tibia 315

Fibula 315

Tarsus, Metatarsus, and Phalanges 315

Surface Anatomy of Lower Limb

Bones 320

FASCIA, VESSELS, AND CUTANEOUS

NERVES OF LOWER LIMB 322

Subcutaneous Tissue and Fascia 322

Venous Drainage of Lower Limb 324

Lymphatic Drainage of Lower Limb 326

Cutaneous Innervation of Lower Limb 326

THIGH AND GLUTEAL REGIONS 329

Anterior Thigh Muscles 329

Medial Thigh Muscles 330

NEUROVASCULAR STRUCTURES AND RELATIONSHIPS IN ANTEROMEDIAL THIGH 331

Femoral Triangle and Adductor Canal 331 Femoral Nerve 335

Femoral Sheath 335 Femoral Artery 336 Femoral Vein 337 Obturator Artery and Nerve 337 GLUTEAL AND POSTERIOR THIGH REGIONS 337

Gluteal Muscles 337 Gluteal Bursae 340 Posterior Thigh Muscles 340 Nerves of Gluteal Region and Posterior Thigh 342

Vasculature of Gluteal and Posterior Thigh Regions 342

POPLITEAL FOSSA 346 Fascia of Popliteal Fossa 346 Vessels in Popliteal Fossa 346 Nerves in Popliteal Fossa 346

LEG 348 Anterior Compartment of Leg 348 Lateral Compartment of Leg 351 Posterior Compartment of Leg 353 FOOT 362

Deep Fascia of Foot 362 Muscles of Foot 363 Nerves of Foot 365 Arteries of Foot 365 Venous Drainage of Foot 367 Lymphatic Drainage of Foot 367 WALKING: THE GAIT CYCLE 367 JOINTS OF LOWER LIMB 369 Hip Joint 369

Knee Joint 374 Tibiofi bular Joints 379 Ankle Joint 385 Joints of Foot 389 Arches of Foot 391 MEDICAL IMAGING OF LOWER LIMB 394

LOWER LIMB 5

as well as the joints between these bony structures; the

fat-filled hollow posterior to the knee (L poples) is called the popliteal fossa.

4 Leg region (L regio cruris) connects the knee and

ankle joints and includes the tibia and fibula; the calf

(L sura) of the leg is the posterior prominence Often,

laypersons refer incorrectly to the entire lower limb as

“the leg.”

5 Ankle or talocrural region (L regio talocruralis)

includes the narrow distal leg and ankle (talocrural) joint

6 Foot region (L regio pedis), the distal part of the lower

limb, contains the tarsus, metatarsus, and phalanges (toe

bones) The superior surface is the dorsum of the foot;

the inferior, ground-contacting surface is the sole or

plantar region The toes are the digits of the foot

As in the hand, digit 1, the great toe (L hallux) has only

two phalanges, and the other digits have three

The lower limbs (extremities) are specialized for locomotion,

supporting body weight, and maintaining balance The lower

limbs are connected to the trunk by the pelvic girdle, a bony

ring composed of the sacrum and right and left hip bones

joined anteriorly at the pubic symphysis (L symphysis

pubis) The lower limb has six major regions (Fig 5.1):

1 Gluteal region (L regio glutealis) is the transitional

zone between the trunk and free lower limbs It includes

the buttocks (L nates, clunes) and hip region (L regio

coxae), which overlies the hip joint and greater trochanter

of the femur

2 Femoral region (L regio femoris), also referred to as

the thigh, includes most of the femur, which connects

the hip and knee joints

3 Knee region (L regio genus) includes the distal femur,

the proximal tibia and fibula, and the patella (knee cap)

1/2 pelvic girdle

2 Femoral

region

(thigh)

4 Leg region

6 Foot

Phalanges Tarsus

Fibula Tibia

Femur

Sacrum

Lumbar vertebra Iliac crest

Coccyx

Bony pelvis Hip bone

Pubic symphysis

Patella

(A) Anterior view

Inguinal ligament

Ischiopubic ramus Greater trochanter

Lateral and medial malleoli

Inguinal

region

Hip joint

1 Gluteal region (buttocks and hip)

5 Ankle

(talocrural)

region

Ankle

(talocrural)

joint

Knee joint

3 Knee

region

Erector spinae muscles

Iliopsoas muscle Rotational

axes of pelvis, hip joint, and knee joint

Plantar flexor muscles (triceps surae)

Rotational axis of ankle joint

Center of gravity

Center

of gravity

(B) Lateral view (C) Inferior view

FIGURE 5.1 Lower limb A Regions and bones of lower limb B and C Center of gravity in a relaxed standing position.

• Internal aspect of the body of the pubis faces almost directly superiorly

• Acetabulum faces inferolaterally, with the acetabular notch directed inferiorly

• Obturator foramen lies inferomedial to the acetabulum

BONES OF LOWER LIMB

Body weight is transferred from the vertebral column

through the sacro-iliac joints to the pelvic girdle and

from the pelvic girdle through the hip joints to the femurs

(L femora) and then through the femurs to the knee

joints Weight is then transferred from the knee joint to

the ankle joint by the tibia The fibula does not articulate

with the femur and does not bear weight At the ankle,

the weight is transferred to the talus The talus is the

keystone of a longitudinal arch formed by the tarsal and

metatarsal bones of each foot, which distribute the weight

evenly between the heel and the forefoot when standing

To support the erect bipedal posture better, the femurs

are oblique (directed inferomedially) within the thighs so

that when standing, the knees are adjacent and are placed

directly inferior to the trunk, returning the center of

grav-ity to the vertical lines of the supporting legs and feet

(Figs 5.1 and 5.2A,E) The femurs of females are slightly

more oblique than those of males, reflecting the greater

width of their pelves

Hip Bone

Each mature hip bone is formed by the fusion of three

primary bones: ilium, ischium, and pubis (Fig 5.3A)

At puberty, these bones are still separated by a triradiate

cartilage The cartilage disappears and the bones begin to

fuse at 15 to 17 years of age; fusion is complete between

20 and 25 years of age

The ilium, the superior and largest part of the hip

bone, contributes to the superior part of the acetabulum

(Fig 5.3), the cup-like cavity (socket) on the lateral aspect of

the hip bone for articulation with the head of the femur The

ilium consists of a body, which joins the pubis and ischium

to the acetabulum, and an ala (wing), which is bordered

superiorly by the iliac crest.

The ischium forms the postero-inferior part of the

acetabulum and hip bone The ischium consists of a body,

where it joins the ilium and superior ramus of the pubis to

form the acetabulum The ramus of the ischium joins the

inferior ramus of the pubis to form the ischiopubic ramus

(Fig 5.3C).

The pubis forms the anterior part of the acetabulum and

the anteromedial part of the hip bone The right pubis has a

body that articulates with the left pubis at the pubic

symphy-sis It also has two rami, superior and inferior.

To place the hip bone or bony pelvis in the anatomical

position (Fig 5.3B,C), situate it so that the

• Anterior superior iliac spine and anterosuperior aspect of

the pubis lie in the same coronal (frontal) plane

• Symphysial surface of the pubis is vertical, parallel to the

median plane

Fractures of Hip Bone

Fractures of the hip bone are “pelvic fractures.”

The term hip fracture is most commonly

applied, unfortunately, to fractures of the femoral heads, neck, or trochanters.

Avulsion fractures of the hip bone may occur during sports that require sudden acceleration or deceleration

A small part of the bone with a piece of tendon or ligament attached is “avulsed” (torn away)—for example, the ante-rior supeante-rior iliac spine In older patients, pelvic fractures often include at least two fractures of the ring of bone formed by the pubis, pubic rami, and the acetabulum

One cannot just break one side of a stiff ring.

Clinical Box

Femur

The femur is the longest and heaviest bone in the body The

femur consists of a shaft (body) and superior or proximal and

inferior or distal ends (Fig 5.2) Most of the shaft is smoothly rounded, except for a prominent double-edged ridge on its

posterior aspect, the linea aspera, which diverges inferiorly

The proximal end of the femur consists of a head, neck, and

greater and lesser trochanters The head of the femur is

covered with articular cartilage, except for a medially placed

depression or pit, the fovea for the ligament of the head The neck of the femur is trapezoidal; the narrow end

supports the head and its broader base is continuous with the shaft

Where the neck joins the shaft are two large, blunt

eleva-tions—the trochanters The conical lesser trochanter, with

its rounded tip, extends medially from the posteromedial

part of the junction of the femoral neck and shaft (Fig 5.2A)

The greater trochanter is a large, laterally placed mass that

projects superomedially where the neck joins the shaft The

intertrochanteric line is a roughened ridge running from

the greater to the lesser trochanter A similar but smoother

ridge, the intertrochanteric crest, joins the trochanters

posteriorly (Fig 5.2B).

The distal end of the femur ends in two spirally curved

femoral condyles (medial and lateral) The femoral

condyles articulate with the tibial condyles to form the knee joint

FIGURE 5.2 Bones of lower limb (continued)

Anterior superior

iliac spine (ASIS)

Anterior inferior

iliac spine

Greater

trochanter

Intertrochanteric

line

Lesser

trochanter

Femur

(A) Anterior view

Patella

Apex of head

Head

Neck

Lateral

malleolus

Calcaneus

Cuboid

Fibula

Lateral femoral

condyle

Medial femoral condyle

Lateral

epicondyle

Tubercle of

iliac crest

Pubic crest Pubic tubercle

Superior ramus

of pubis

Iliopubic eminence

Pubic symphysis Body of pubis Obturator foramen

Head of femur

Adductor tubercle Medial epicondyle

Medial tibial condyle Intercondylar eminence Tuberosity Anterior border Lateral surface Medial surface

Medial malleolus

Tibia

Talus

Cuneiforms Navicular

First metatarsal Proximal phalanx Distal phalanx

Hip bone

Intertrochanteric line

Head

of femur

Fovea for ligament of head

Apex

Apex Base

Base

(B) Anterior view of proximal femur

Greater trochanter

Neck of femur

Shaft

of femur

Lesser trochanter

Medial border

Lateral border

Lateral articular surface

Medial articular surface

(D) Posterior view of patella (C) Anterior view of patella

(E) Posterior view

Medial femoral condyle

Posterior gluteal line

Posterior superior iliac spine (PSIS)

Posterior inferior iliac spine

Greater sciatic notch

Lesser sciatic notch

Ischial tuberosity Acetabulum Ischial spine

Iliac crest Tubercle of iliac crest

Inferior gluteal line

Greater trochanter

Neck of femur

Femur

Lateral femoral condyle

Lateral tibial condyle

Head Popliteal surface

Lesser trochanter

Linea aspera

Intertrochanteric crest

Gluteal tuberosity

Ischium

Head of femur Anterior gluteal line

Spiral line Lateral supracondylar line

Medial supracondylar line

Intercondylar fossa

Neck

Lateral malleolus

Calcaneus Cuboid 5th metatarsal Fibula

Adductor tubercle

Medial tibial condyle

Soleal line Vertical line

Tibia

Medial cuneiform

Medial malleolus

Talus

Navicular

Hip bone

Phalanx

Proximal Middle Distal

FIGURE 5.2 Bones of lower limb (continued)

Inferior gluteal line

Ramus of ischium

Inferior ramus of pubis

Anterior inferior iliac spine

Anterior superior iliac spine (ASIS)

Articular (lunate) surface Acetabular fossa

*Ischiopubic ramus

£Acetabulum

Pubic crest Acetabular notch

Pubic tubercle

*

£

Obturator groove

(C) Lateral aspect

Iliac crest

Anterior gluteal line

Posterior gluteal line

Posterior inferior iliac spine

Posterior superior iliac spine (PSIS)

Greater sciatic notch

Ischial spine Lesser sciatic notch

Ischial tuberosity

Body of ischium Obturator foramen

Position of triradiate cartilage

Ala

Body

Acetabulum

(A) Lateral aspect

(B) Medial aspect

(D) Medial aspect

Iliac crest

Obturator foramen Body of pubis

Superior ramus

of pubis Pecten pubis

Iliopubic eminence Arcuate line

Anterior inferior iliac spine

Anterior superior iliac spine

Iliac fossa

*Ischiopubic ramus

Greater sciatic notch

Ischial spine

Lesser sciatic notch

Ischial tuberosity

Ramus of ischium*

Inferior ramus of pubis*

Posterior superior iliac spine

Posterior inferior iliac spine

Body of ischium

Auricular surface

of ilium Tuberosity of ilium

Ilium Pubis Ischium

Parts of the hip bone

FIGURE 5.3 Hip bone A and B Parts of hip bone of a 13-year-old C and D Right hip bone of an adult in anatomical position In this position, the

anterior superior iliac spine (ASIS) and the anterior aspect of the pubis lie in the same vertical plane (indicated in blue).

is smooth, covered with a thick layer of articular cartilage, and is divided into medial and lateral articular surfaces by a

vertical ridge (Fig 5.2C,D).

Tibia

The large, weight-bearing tibia (shin bone) articulates with the femoral condyles superiorly, the talus inferiorly, and the fibula laterally at its proximal and distal ends (Fig 5.2) The distal end of the tibia is smaller than the proximal end and has facets for articulation with the fibula and talus The

medial malleolus is an inferiorly directed projection from

the medial side of the distal end of the tibia (Fig 5.5A) The

large nutrient foramen of the tibia is located on the

pos-terior aspect of the proximal third of the bone (Fig 5.5B)

From it, the nutrient canal runs inferiorly in the tibia before

it opens into the medullary (marrow) cavity For other bony features, see Figure 5.5

Fibula

The slender fibula lies posterolateral to the tibia and serves mainly for muscle attachment (Figs 5.2 and 5.5) At its

prox-imal end, the fibula consists of an enlarged head superior to

a narrow neck At its distal end, the fibula enlarges to form

the lateral malleolus, which is more prominent and more

posteriorly placed than the medial malleolus and extends approximately 1 cm farther distally The fibula is not directly involved in weight bearing; however, its lateral malleolus forms the lateral part of the socket for the trochlea of the talus The shafts of the tibia and fibula are connected by an

interosseous membrane throughout most of their lengths.

Tarsus, Metatarsus, and Phalanges

The bones of the foot include the tarsus, metatarsus, and

phalanges (Figs 5.2 and 5.6)

The proximal femur is bent, making the femur L-shaped,

so that the long axis of the head and neck project

supero-medially at an angle to that of the obliquely oriented shaft

(Fig 5.4) This obtuse angle of inclination in the adult

is 115 to 140 degrees, averaging 126 degrees The angle is

less in females because of the increased width between the

acetabula and the greater obliquity of the shaft The angle

of inclination allows greater mobility of the femur at the hip

joint because it places the head and neck more

perpendicu-lar to the acetabulum This is advantageous for bipedal

walk-ing; however, it imposes considerable strain on the neck of

the femur Fractures of the neck may occur in older people

as a result of a slight stumble if the neck has been weakened

by osteoporosis

When the femur is viewed superiorly, so that the

proxi-mal end is superimposed over the distal end (Fig 5.4D), it

can be seen that the axis of the head and neck of the femur

and the transverse axis of the femoral condyles intersect at

the long axis of the shaft of the femur, forming the torsion

angle, or angle of declination The mean torsion angle is

7 degrees in males and 12 degrees in females The torsion

angle, combined with the angle of inclination, allows

rota-tory movements of the femoral head within the obliquely

placed acetabulum to convert into flexion and extension,

abduction and adduction, and rotational movements of

the thigh

Patella

The patella (knee cap) is a large sesamoid bone that is

formed intratendinously after birth This triangular bone,

located anterior to the femoral condyles, articulates with

the patellar surface of the femur (Fig 5.2A,C) The

sub-cutaneous anterior surface of the patella is convex; the

thick base (superior border) slopes infero-anteriorly; the

lateral and medial borders converge inferiorly to form the

pointed apex; and the articular surface (posterior surface)

(A) Angle of inclination (B) (C)

in 3-year-old child

Angle of inclination

in adult

Angle of inclination

in old age

(D) Superior view demonstrating torsion angle of femur

Axis of femoral head and neck

Trochanteric fossa

Torsion angle

of femur

Long axis of shaft of femur

Inferior (distal) end of femur

Transverse axis of femoral condyles

Greater trochanter

126˚

120˚

126˚

120˚

FIGURE 5.4 Angle of inclination and torsion angle of femur.

Intercondylar tubercles of intercondylar eminence

Medial condyle

Tibial tuberosity

Anterior border

Shaft (body)

of tibia

Shaft of tibia

Medial malleolus

Apex of head

Lateral condyle

Head of fibula

Anterolateral

tibial (Gerdy)

tubercle (G)

Interosseous

border

Anterior border

Shaft of fibula

Lateral malleolus

(A) Anterior view (right side)

Intercondylar tubercles of intercondylar eminence

Medial condyle

Medial tibial plateau

Lateral condyle

Lateral tibial plateau

Apex of head

Posterior intercondylar area Soleal line

Head of fibula (contacting fibular articular facet of tibia) Medial crest

Nutrient foramen

Medial border

Interosseous membrane

Interosseous membrane Opening for

anterior tibial

vessels

Interosseous border

Posterior border

Fibular notch of tibia, occupied

by fibula

Groove for tibialis posterior tendon Fibular notch

of tibia occupied

by fibula

Medial

malleolus

(B) Posterior view (right side)

Anterior intercondylar area

Lateral surface

Medial

Lateral tibial plateau Medial tibial plateau

Shaft of fibula

G

Neck of fibula

FIGURE 5.5 Right tibia and fibula The shafts are connected by the interosseous membrane composed of strong obliquely oriented fibers.

TARSUS

The tarsus consists of seven bones: calcaneus, talus, cuboid,

navicular, and three cuneiforms Only the talus articulates

with the leg bones The calcaneus (heel bone) is the

larg-est and stronglarg-est bone in the foot It articulates with the

talus superiorly and the cuboid anteriorly (Fig 5.6A) The

calcaneus transmits most of the body weight from the talus

to the ground The sustentaculum tali (talar shelf),

pro-jecting from the superior border of the medial surface of

the calcaneus, supports the head of the talus (Fig 5.6B)

The posterior part of the calcaneus has a large prominence,

the calcaneal tuberosity (L tuber calcanei), which has

medial and lateral processes on its plantar aspect More

anteriorly, there is a smaller prominence, the calcaneal

tubercle (Fig 5.6B).

The talus (ankle bone) has a head, neck, and body

(Fig 5.6C) The superior surface, the trochlea of the

talus, bears the weight of the body transmitted from the

tibia and articulates with the two malleoli The talus rests

on the anterior two thirds of the calcaneus Most of the

surface of the talus is covered with articular cartilage, and

thus no muscles or tendons attach to the talus The rounded

head of talus rests partially on the sustentaculum tali of

the calcaneus and articulates anteriorly with the navicular

(Fig 5.6B,E).

The navicular (L little ship), a flattened, boat-shaped

bone, is located between the talar head and the cuneiforms

The medial surface of the navicular projects inferiorly as

the tuberosity of navicular An overly prominent

tuber-osity may press against the medial part of the shoe and cause foot pain

The cuboid is the most lateral bone in the distal row

of the tarsus Anterior to the tuberosity of cuboid

(Fig 5.6B), on the lateral and plantar surfaces of the bone,

is a groove for the tendon of the fibularis longus muscle

(Fig 5.6B,C).

There are three cuneiforms: medial (first),

inter-mediate (second), and lateral (third) Each cuneiform

(L cuneus, wedge-shaped) articulates with the navicular

posteriorly and the base of the appropriate metatarsal anteriorly In addition, the lateral cuneiform articulates with the cuboid

Calcaneal tuberosity

Medial process Sustentaculum tali Head of talus Tuberosity of navicular Medial cuneiform (M) Intermediate cuneiform (I) Lateral cuneiform (L)

Proximal phalanx Distal phalanx

Groove for fibular longus Tuberosity of 5th metatarsal Tuberosity of cuboid Cuboid Calcaneal tubercle

Lateral process

5 4 3

(B) Plantar view

Distal Middle Proximal

Cuboid Navicular Talus Trochlea of talus

Groove for tendon of flexor hallucis longus Calcaneus

Phalanges Head

Shaft Base

Medial tubercle Lateral tubercle

1st

metatarsal

Tarsus

(A) Dorsal view

M I L

1 2 3 4 5

(E) Medial view

(D) Lateral view

(C) Lateral view

(F) Medial view

Calcaneus

Body Neck Head

Of talus

Navicular Cuneiforms (lateral and intermediate)

Metatarsals (2–5)

Phalanges

Lateral malleolus

Calcaneus

Head Tubercle

Shaft Base Cuboid

Tuberosity of 5th metatarsal

Groove for fibularis longus Fibular trochlea

Of talus Neck Body Navicular

Medial cuneiform 1st metatarsal

Proximal phalanx Distal

phalanx

Sustentaculum tali

Calcaneus

Cuboid Lateral cuneiform

Tuberosity of 5th metatarsal

Cuboid

Medial malleolus

Tuberosity

of navicular

Medial cuneiform

Tuberosity of 1st metatarsal Head of 1st metatarsal

*of tuberosity

*

FIGURE 5.6 Bones of foot Blue, articular cartilage.

The metatarsus consists of five long bones

(metatar-sals), which connect the tarsus and phalanges They are

numbered from the medial side of the foot (Fig 5.6B,C)

The 1st metatarsal is shorter and stouter than the

oth-ers The 2nd metatarsal is the longest Each metatarsal

has a base (proximally), a shaft, and a head (distally)

The bases of the metatarsals articulate with the

cunei-form and cuboid bones The bases of the 1st and 5th

metatarsals have large tuberosities; the tuberosity of

the 5th metatarsal projects over the lateral margin of

the cuboid (Fig 5.6C) The heads articulate with the

proximal phalanges

PHALANGES

There are 14 phalanges The 1st digit (great toe) has

two phalanges (proximal and distal); the other four digits each have three phalanges: proximal, middle, and distal

(Fig 5.6A,B) Each phalanx has a base (proximally), a shaft,

and a head (distally)

Clinical Box

Femoral Fractures

The neck of the femur is most frequently fractured, especially in females secondary to osteoporosis

Fractures of the proximal femur can occur at

sev-eral locations—for example, transcervical and intertrochanteric

(Fig B5.1A,B) The femoral shaft is large and strong;

how-ever, a violent direct injury, such as may be sustained in an

automobile accident, may fracture it, causing, for example, a

spiral fracture (Fig B5.1C) Fractures of the distal femur may

be complicated by separation of the condyles, resulting in

misalignment of the knee joint.

Coxa Vara and Coxa Valga

The angle of inclination varies with age, sex, and development of the femur (e.g., consequent to a congenital defect in ossification of the femoral neck) It also may change with any pathological process that weakens the neck of the femur (e.g., rickets) When the

angle of inclination is decreased, the condition is coxa vara

(Fig B5.2A); when it is increased, the condition is coxa valga

(Fig B5.2B) Coxa vara causes a mild passive abduction of

the hip.

FIGURE B5.1 Femoral fractures.

(A) Transcervical fracture

of femoral neck

(C) Spiral fracture Anterior views

(B) Intertrochanteric fracture

FIGURE B5.2 Coxa vara and coxa valga.

(A) Coxa vara (decreased angle

of inclination)

(B) Coxa valga (increased angle

of inclination) Posterior views