Ligaments of the Gluteal Region-Sacrotuberous Ligament-Sacrospinous Ligament-Greater Sciatic Foramen-Foramina of the Gluteal Region-Lesser Sciatic Foramen-Muscles of the Gluteal Region-

Ligaments of the Gluteal Region

The two important ligaments in the gluteal region are the sacrotuberous and sacrospinous ligaments. The function of these ligaments is to stabilize the sacrum and prevent its rotation at the sacroiliac joint by the weight of the vertebral column.

Sacrotuberous Ligament

The sacrotuberous ligament connects the back of the sacrum to the ischial tuberosity.

Sacrospinous Ligament

The sacrospinous ligament connects the back of the sacrum to the spine of the ischium.

Foramina of the Gluteal Region

The two important foramina in the gluteal region are the greater sciatic foramen and the lesser sciatic foramen.

Greater Sciatic Foramen

The greater sciatic foramen is formed by the greater sciatic notch of the hip bone and the sacrotuberous and sacrospinous ligaments. It provides an exit from the pelvis into the gluteal region.

The following structures exit the foramen:

■■ Piriformis

■■ Sciatic nerve

■■ Posterior cutaneous nerve of the thigh

■■ Superior and inferior gluteal nerves

■■ Nerves to the obturator internus and quadratus femoris

■■ Pudendal nerve

■■ Superior and inferior gluteal arteries and veins

■■ Internal pudendal artery and vein

Lesser Sciatic Foramen

The lesser sciatic foramen is formed by the lesser sciatic notch of the hip bone and the sacrotuberous and sacrospinous ligaments. It provides an entrance into the perineum from the gluteal region. Its presence enables nerves and blood vessels that have left the pelvis through the greater sciatic foramen above the pelvic floor to enter the perineum below the pelvic floor.

The following structures pass through the foramen

■■ Tendon of obturator internus muscle

■■ Nerve to obturator internus

■■ Pudendal nerve

■■ Internal pudendal artery and vein

Muscles of the Gluteal Region

The muscles of the gluteal region include the gluteus maximus, the gluteus medius, the gluteus minimus, the tensor fasciae latae, the piriformis, the obturator internus, the superior and inferior gemelli, and the quadratus femoris.

Note the following:

■■ The gluteus maximus is the largest muscle in the body. It lies superficial in the gluteal region and is largely responsible for the prominence of the buttock.

■■ The tensor fasciae latae runs downward and backward to its insertion in the iliotibial tract and thus assists the gluteus maximus muscle in maintaining the knee in the extended position.

 

Fractures of the Femur-

Fractures of the Femur

Fractures of the neck of the femur are common and are of two types, subcapital and trochanteric. The subcapital fracture occurs in the elderly and is usually produced by a minor trip or stumble. Subcapital femoral neck fractures are particularly common in women after menopause. This gender predisposition is because of a thinning of the cortical and trabecular bone caused by estrogen deficiency. Avascular necrosis of the head is a common complication. If the fragments are not impacted, considerable displacement occurs. The strong muscles of the thigh, including the rectus femoris, the adductor muscles, and the hamstring muscles, pull the distal fragment upward, so that the leg is shortened (as measured from the anterior superior iliac spine to the adductor tubercle or medial malleolus). The gluteus maximus, the piriformis, the obturator internus, the gemelli, and the quadratus femoris rotate the distal fragment laterally, as seen by the toes pointing laterally.

Trochanteric fractures commonly occur in the young and middle aged as a result of direct trauma. The fracture line is extracapsular, and both fragments have a profuse blood supply. If the bone fragments are not impacted, the pull of the strong muscles will produce shortening and lateral rotation of the leg, as previously explained.

Fractures of the shaft of the femur usually occur in young and healthy persons. In fractures of the upper third of the shaft of the femur, the proximal fragment is flexed by the iliopsoas; abducted by the gluteus medius and minimus; and laterally rotated by the gluteus maximus, the piriformis, the obturator internus, the gemelli, and the quadratus femoris. The lower fragment is adducted by the adductor muscles, pulled upward by the hamstrings and quadriceps, and laterally rotated by the adductors and the weight of the foot.

In fractures of the middle third of the shaft of the femur, the distal fragment is pulled upward by the hamstrings and the quadriceps , resulting in considerable shortening. The distal fragment is also rotated backward by the pull of the two heads of the gastrocnemius. In fractures of the distal third of the shaft of the femur, the same displacement of the distal fragment occurs as seen in fractures of the middle third of the shaft. However, the distal fragment is smaller and is rotated backward by the gastrocnemius muscle to a greater degree and may exert pressure on the popliteal artery and interfere with the blood flow through the leg and foot.

From these accounts, it is clear that knowledge of the different actions of the muscles of the leg is necessary to understand the displacement of the fragments of a fractured femur.

Considerable traction on the distal fragment is usually required to overcome the powerful muscles and restore the limb to its correct length before manipulation and operative therapy to bring the proximal and distal fragments into correct alignment

Brachial Plexus Injuries-Lower Lesions of the Brachial Plexus (Klumpke Palsy)-Long Thoracic Nerve

Brachial Plexus Injuries

The roots, trunks, and divisions of the brachial plexus reside in the lower part of the posterior triangle of the neck, whereas the cords and most of the branches of the plexus lie in the axilla.

Complete lesions involving all the roots of the plexus are rare.

Incomplete injuries are common and are usually caused by traction or pressure; individual nerves can be divided by stab wounds.

Upper Lesions of the Brachial Plexus (Erb–Duchenne Palsy) Upper lesions of the brachial plexus are injuries resulting from excessive displacement of the head to the opposite side and depression of the shoulder on the same side. This causes excessive traction or even tearing of C5 and 6 roots of the plexus. It occurs in infants during a difficult delivery or in adults after a blow to or fall on the shoulder. The suprascapular nerve, the nerve to the subclavius, and the musculocutaneous and axillary nerves all possess nerve fibers derived from C5 and 6 roots and will therefore be functionless. The following muscles will consequently be paralyzed: the supraspinatus (abductor of the shoulder) and infraspinatus (lateral rotator of the shoulder); the subclavius (depresses the clavicle); the biceps brachii (supinator of the forearm, flexor of the elbow, weak flexor of the shoulder) and the greater part of the brachialis (flexor of the elbow) and the coracobrachialis (flexes the shoulder); and the deltoid (abductor of the shoulder) and the teres minor (lateral rotator of the shoulder).

Thus, the limb will hang limply by the side, medially rotated by the unopposed sternocostal part of the pectoralis major; the forearm will be pronated because of loss of the action of the biceps. The position of the upper limb in this condition has been likened to that of a porter or waiter hinting for a tip. In addition, there will be a loss of sensation down the lateral side of the arm.

Lower Lesions of the Brachial Plexus (Klumpke Palsy)

Lower lesions of the brachial plexus are usually traction injuries caused by excessive abduction of the arm, as occurs in the case of a person falling from a height clutching at an object to save himself or herself. The 1st thoracic nerve is usually torn.

The nerve fibers from this segment run in the ulnar and median nerves to supply all the small muscles of the hand. The hand has a clawed appearance caused by hyperextension of the metacarpophalangeal joints and flexion of the interphalangeal joints. The extensor digitorum is unopposed by the lumbricals and interossei and extends the metacarpophalangeal joints; the flexor digitorum superficialis and profundus are unopposed by the lumbricals and interossei and flex the middle and terminal phalanges, respectively.

In addition, loss of sensation will occur along the medial side of the arm. If the 8th cervical nerve is also damaged, the extent of anesthesia will be greater and will involve the medial side of the forearm, hand, and medial two fingers.

Lower lesions of the brachial plexus can also be produced by the presence of a cervical rib or malignant metastases from the lungs in the lower deep cervical lymph nodes.

Long Thoracic Nerve

The long thoracic nerve, which arises from C5, 6, and 7 and supplies the serratus anterior muscle, can be injured by blows to or pressure on the posterior triangle of the neck or during the surgical procedure of radical mastectomy. Paralysis of the serratus anterior results in the inability to rotate the scapula during the movement of abduction of the arm above a right angle.

The patient therefore experiences difficulty in raising the arm above the head. The vertebral border and inferior angle of the scapula will no longer be kept closely applied to the chest wall and will protrude posteriorly, a condition known as “winged scapula”

Arterial Injury of the upper limb-Palpation and Compression of Arteries-Allen Test-Arterial Innervation and Raynaud’s Disease-

Arterial Injury of the upper limb

The arteries of the upper limb can be damaged by penetrating wounds or may require ligation in amputation operations.

Because of the existence of an adequate collateral circulation around the shoulder, elbow, and wrist joints, ligation of the main arteries of the upper limb is not followed by tissue necrosis or gangrene, provided, of course, that the arteries forming the collateral circulation are not diseased and the patient’s general circulation is satisfactory. Nevertheless, it can take days or weeks for the collateral vessels to open sufficiently to provide the distal part of the limb with the same volume of blood as previously supplied by the main artery.

Palpation and Compression of Arteries

A clinician must know where the arteries of the upper limb can be palpated or compressed in an emergency. The subclavian artery, as it crosses the first rib to become the axillary artery, can be palpated in the root of the posterior triangle of the neck. The artery can be compressed here against the first rib to stop a catastrophic hemorrhage. The third part of the axillary artery can be felt in the axilla as it lies in front of the teres major muscle. The brachial artery can be palpated in the arm as it lies on the brachialis and is overlapped from the lateral side by the biceps brachii.

The radial artery lies superficially in front of the distal end of the radius, between the tendons of the brachioradialis and flexor carpi radialis; it is here that the clinician takes the radial pulse. If the pulse cannot be felt, try feeling for the radial artery on the other wrist; occasionally, a congenitally abnormal radial artery can be difficult to feel. The radial artery can be less easily felt as it crosses the anatomic snuffbox.

The ulnar artery can be palpated as it crosses anterior to the flexor retinaculum in company with the ulnar nerve. The artery lies lateral to the pisiform bone, separated from it by the ulnar nerve. The artery is commonly damaged here in laceration wounds in front of the wrist.

Allen Test

The Allen test is used to determine the patency of the ulnar and radial arteries. With the patient’s hands resting in the lap, compress the radial arteries against the anterior surface of each radius and ask the patient to tightly clench the fists. The clenching of the fists closes off the superficial and deep palmar arterial arches. When the patient is asked to open the hands, the skin of the palms is at first white, and then normally the blood quickly flows into the arches through the ulnar arteries, causing the palms to promptly turn pink. This establishes that the ulnar arteries are patent. The patency of the radial arteries can be established by repeating the test but this time compressing the ulnar arteries as they lie lateral to the pisiform bones.

Arterial Innervation and Raynaud’s Disease

The arteries of the upper limb are innervated by sympathetic nerves. The preganglionic fibers originate from cell bodies in the 2nd to 8th thoracic segments of the spinal cord. They ascend in the sympathetic trunk and synapse in the middle cervical, inferior cervical, 1st thoracic, or stellate ganglia. The postganglionic fibers join the nerves that form the brachial plexus and are distributed to the arteries within the branches of the plexus.

For example, the digital arteries of the fingers are supplied by postganglionic sympathetic fibers that run in the digital nerves. Vasospastic diseases involving digital arterioles, such as Raynaud’s disease, may require a cervicodorsal preganglionic sympathectomy to prevent necrosis of the fingers. The operation is followed by arterial vasodilatation, with consequent increased blood flow to the upper limb.

The Wrist and Hand-Important Structures Lying in Front of the Wrist-Radial Artery-Tendon of Flexor Carpi Radialis-Tendon of Palmaris Longus (If Present)-Tendons of Flexor Digitorum Superficialis-Tendon of Flexor Carpi Ulnaris-Ulnar Artery-Ulnar Nerve-Important Structures Lying on the Lateral Side of the Wrist-Anatomic Snuffbox-Important Structures Lying on the Back of the Wrist-Lunate-Important Structures Lying in the Palm-Recurrent Branch of the Median Nerve-Superficial Palmar Arterial Arch-Important Structures Lying on the Dorsum of the Hand

The Wrist and Hand

At the wrist, the styloid processes of the radius and ulna can be palpated. The styloid process of the radius lies about 0.75 in. (1.9 cm) distal to that of the ulna.

The dorsal tubercle of the radius is palpable on the posterior surface of the distal end of the radius.

The head of the ulna is most easily felt with the forearm pronated; the head then stands out prominently on the lateral side of the wrist. The rounded head can be distinguished from the more distal pointed styloid process.

The pisiform bone can be felt on the medial side of the anterior aspect of the wrist between the two transverse creases. The hook of the hamate bone can be felt on deep palpation of the hypothenar eminence, a fingerbreadth distal and lateral to the pisiform bone.

The transverse creases seen in front of the wrist are important landmarks. The proximal transverse crease lies at the level of the wrist joint. The distal transverse crease corresponds to the proximal border of the flexor retinaculum.

Important Structures Lying in Front of the Wrist

Radial Artery

The pulsations of the radial artery can easily be felt anterior to the distal third of the radius. Here, it lies just beneath the skin and fascia lateral to the tendon of flexor carpi radialis muscle

Tendon of Flexor Carpi Radialis
The tendon of the flexor carpi radialis lies medial to the pulsating radial artery
.

Tendon of Palmaris Longus (If Present)

The tendon of the palmaris longus lies medial to the tendon of flexor carpi radialis and overlies the median nerve

Tendons of Flexor Digitorum Superficialis

The tendons of the flexor digitorum superficialis are a group of four that lie medial to the tendon of palmaris longus and can be seen moving beneath the skin when the fingers are flexed and extended.

 

Tendon of Flexor Carpi Ulnaris

The tendon of the flexor carpi ulnaris is the most medially placed tendon on the front of the wrist and can be followed distally to its insertion on the pisiform bone. The tendon can be made prominent by asking the patient to clench the fist (the muscle contracts to assist in fixing and stabilizing the wrist joint)
.

Ulnar Artery

The pulsations of the ulnar artery can be felt lateral to the tendon of flexor carpi ulnaris

Ulnar Nerve

The ulnar nerve lies immediately medial to the ulnar artery

Important Structures Lying on the Lateral Side of the Wrist

Anatomic Snuffbox

The “anatomic snuffbox” is an important area. It is a skin depression that lies distal to the styloid process of the radius. It is bounded medially by the tendon of extensor pollicis longus and laterally by the tendons of abductor pollicis longus and extensor pollicis brevis. In its floor can be palpated the styloid process of the radius (proximally) and the base of the first metacarpal bone of the thumb (distally); between these bones beneath the floor lie the scaphoid and the trapezium (felt but not identifiable).

The radial artery can be palpated within the snuffbox as the artery winds around the lateral margin of the wrist to reach the dorsum of the hand. The cephalic vein can also sometimes be recognized crossing the snuffbox as it ascends the forearm.

Important Structures Lying on the Back of the Wrist

Lunate

The lunate lies in the proximal row of carpal bones. It can be palpated just distal to the dorsal tubercle of the radius when the wrist joint is flexed.

Important Structures Lying in the Palm

Recurrent Branch of the Median Nerve

The recurrent branch to the muscles of the thenar eminence curves around the lower border of the flexor retinaculum and lies about one fingerbreadth distal to the tubercle of the scaphoid

Superficial Palmar Arterial Arch

The superficial palmar arterial arch is located in the central part of the palm and lies on a line drawn across the palm at the level of the distal border of the fully extended thumb

Deep Palmar Arterial Arch

The deep palmar arterial arch is also located in the central part of the palm and lies on a line drawn across the palm at the level of the proximal border of the fully extended thumb

Metacarpophalangeal Joints

The metacarpophalangeal joints lie approximately at the level of the distal transverse palmar crease. The interphalangeal joints lie at the level of the middle and distal finger creases.

Important Structures Lying on the Dorsum of the Hand

The tendons of extensor digitorum, the extensor indicis, and the extensor digiti minimi can be seen and felt as they pass distally to the bases of the fingers.