Wrist Joint (Radiocarpal Joint)-Movements-Important Relations-Wrist Joint Injuries-Falls on the Outstretched Hand-

Wrist Joint (Radiocarpal Joint)

■■ Articulation: Between the distal end of the radius and the articular disc above and the scaphoid, lunate, and triquetral bones below. The proximal articular surface forms an ellipsoid concave surface, which is adapted to the distal ellipsoid convex surface.

■■ Type: Synovial ellipsoid joint

■■ Capsule: The capsule encloses the joint and is attached above to the distal ends of the radius and ulna and below to the proximal row of carpal bones.

■■ Ligaments: Anterior and posterior ligaments strengthen the capsule. The medial ligament is attached to the styloid process of the ulna and to the triquetral bone. The lateral ligament is attached to the styloid process of the radius and to the scaphoid bone.

■■ Synovial membrane: This lines the capsule and is attached to the margins of the articular surfaces. The joint cavity does not communicate with that of the distal radioulnar joint or with the joint cavities of the intercarpal joints.

■■ Nerve supply: Anterior interosseous nerve and the deep branch of the radial nerve

Movements

The following movements are possible: flexion, extension, abduction, adduction, and circumduction. Rotation is not possible because the articular surfaces are ellipsoid shaped.

The lack of rotation is compensated for by the movements of pronation and supination of the forearm.

Flexion is performed by the flexor carpi radialis, the flexor carpi ulnaris, and the palmaris longus. These muscles are assisted by the flexor digitorum superficialis, the flexor digitorum profundus, and the flexor pollicis longus.

Extension is performed by the extensor carpi radialis longus, the extensor carpi radialis brevis, and the extensor carpi ulnaris. These muscles are assisted by the extensor digitorum, the extensor indicis, the extensor digiti minimi, and the extensor pollicis longus.

Abduction is performed by the flexor carpi radialis and the extensor carpi radialis longus and brevis. These muscles are assisted by the abductor pollicis longus and extensor pollicis longus and brevis.

Adduction is performed by the flexor and extensor carpi ulnaris.

Important Relations

■■ Anteriorly: The tendons of the flexor digitorum profundus and superficialis, the flexor pollicis longus, the flexor carpi radialis, the flexor carpi ulnaris, and the median and ulnar nerves

■■ Posteriorly: The tendons of the extensor carpi ulnaris, the extensor digiti minimi, the extensor digitorum, the extensor indicis, the extensor carpi radialis longus and brevis, the extensor pollicis longus and brevis, and the abductor pollicis longus

■■ Medially: The posterior cutaneous branch of the ulnar nerve

■■ Laterally: The radial artery

Wrist Joint Injuries

The wrist joint is essentially a synovial joint between the distal end of the radius and the proximal row of carpal bones. The head of the ulna is separated from the carpal bones by the strong triangular fibrocartilaginous ligament, which separates the wrist joint from the distal radioulnar joint. The joint is stabilized by the strong medial and lateral ligaments.

Because the styloid process of the radius is longer than that of the ulna, abduction of the wrist joint is less extensive than adduction. In flexion–extension movements, the hand can be flexed about 80° but extended to only about 45°. The range of flexion is increased by movement at the midcarpal joint.

A fall on the outstretched hand can strain the anterior ligament of the wrist joint, producing synovial effusion, joint pain, and limitation of movement. These symptoms and signs must not be confused with those produced by a fractured scaphoid or dislocation of the lunate bone, which are similar.

Falls on the Outstretched Hand

In falls on the outstretched hand, forces are transmitted from the scaphoid to the distal end of the radius, from the radius across the interosseous membrane to the ulna, and from the ulna to the humerus; thence, through the glenoid fossa of the scapula to the coracoclavicular ligament and the clavicle; and finally, to the sternum. If the forces are excessive, different parts of the upper limb give way under the strain. The area affected seems to be related to age. In a young child, for example, there may be a posterior displacement of the distal radial epiphysis; in the teenager the clavicle might fracture; in the young adult the scaphoid is commonly fractured; and in the elderly the distal end of the radius is fractured about 1 in. (2.5 cm) proximal to the wrist joint (Colles’ fracture).

Acromioclavicular Joint-Movements-Important Relations-Acromioclavicular Joint Injuries-Acromioclavicular Dislocation-

Acromioclavicular Joint

■■ Articulation: This occurs between the acromion of the scapula and the lateral end of the clavicle.

■■ Type: Synovial plane joint

■■ Capsule: This surrounds the joint and is attached to the margins of the articular surfaces.

■■ Ligaments: Superior and inferior acromioclavicular ligaments reinforce the capsule; from the capsule, a wedge-shaped fibrocartilaginous disc projects into the joint cavity from above.

■■ Accessory ligament: The very strong coracoclavicular ligament extends from the coracoid process to the undersurface of the clavicle. It is largely responsible for suspending the weight of the scapula and the upper limb from the clavicle.

■■ Synovial membrane: This lines the capsule and is attached to the margins of the cartilage covering the articular surfaces.

■■ Nerve supply: The suprascapular nerve

Movements

A gliding movement takes place when the scapula rotates or when the clavicle is elevated or depressed.

Important Relations

■■ Anteriorly: The deltoid muscle

■■ Posteriorly: The trapezius muscle

■■ Superiorly: The skin

Acromioclavicular Joint Injuries

The plane of the articular surfaces of the acromioclavicular joint passes downward and medially so that there is a tendency for the lateral end of the clavicle to ride up over the upper surface of the acromion. The strength of the joint depends on the strong coracoclavicular ligament, which binds the coracoid process to the undersurface of the lateral part of the clavicle. The greater part of the weight of the upper limb is transmitted to the clavicle through this ligament, and rotary movements of the scapula occur at this important ligament.

Acromioclavicular Dislocation

A severe blow on the point of the shoulder, as is incurred during blocking or tackling in football or any severe fall, can result in the acromion being thrust beneath the lateral end of the clavicle, tearing the coracoclavicular ligament. This condition is known as shoulder separation. The displaced outer end of the clavicle is easily palpable. As in the case of the sternoclavicular joint, the dislocation is easily reduced, but withdrawal of support results in immediate redislocation.

Sternoclavicular Joint-Movements-Muscles Producing Movement-Important Relations-Sternoclavicular Joint Injuries-Anterior dislocation-Posterior dislocation-

Sternoclavicular Joint

■■ Articulation: This occurs between the sternal end of the clavicle, the manubrium sterni, and the 1st costal cartilage

■■ it s type of joints is: Synovial double-plane joint

■■ Capsule: This surrounds the joint and is attached to the margins of the articular surfaces.

■■ Ligaments: The capsule is reinforced in front of and behind the joint by the strong sternoclavicular ligaments.

■■ Articular disc: This flat fibrocartilaginous disc lies within the joint and divides the joint’s interior into two compartments. Its circumference is attached to the interior of the capsule, but it is also strongly attached to the superior margin of the articular surface of the clavicle above and to the first costal cartilage below.

■■ Accessory ligament: The costoclavicular ligament is a strong ligament that runs from the junction of the 1st rib with the 1st costal cartilage to the inferior surface of the sternal end of the clavicle.

■■ Synovial membrane: This lines the capsule and is attached to the margins of the cartilage covering the articular surfaces.

■■ Nerve supply: The supraclavicular nerve and the nerve to the subclavius muscle.

Movements

Forward and backward movement of the clavicle takes place in the medial compartment. Elevation and depression of the clavicle take place in the lateral compartment.

Muscles Producing Movement

The forward movement of the clavicle is produced by the serratus anterior muscle. The backward movement is produced by the trapezius and rhomboid muscles. Elevation of the clavicle is produced by the trapezius, sternocleidomastoid, levator scapulae, and rhomboid muscles. Depression of the clavicle is produced by the pectoralis minor and the subclavius muscles.

Important Relations

■■ Anteriorly: The skin and some fibers of the sternocleidomastoid and pectoralis major muscles

■■ Posteriorly: The sternohyoid muscle; on the right, the brachiocephalic artery; on the left, the left brachiocephalic vein and the left common carotid artery

Sternoclavicular Joint Injuries

The strong costoclavicular ligament firmly holds the medial end of the clavicle to the 1st costal cartilage. Violent forces directed along the long axis of the clavicle usually result in fracture of that bone, but dislocation of the sternoclavicular joint takes place occasionally.

Anterior dislocation
 results in the medial end of the clavicle projecting forward beneath the skin; it may also be pulled upward by the sternocleidomastoid muscle.

Posterior dislocation
 usually follows direct trauma applied to the front of the joint that drives the clavicle backward. This type is the more serious one because the displaced clavicle may press on the trachea, the esophagus, and major blood vessels in the root of the neck.

If the costoclavicular ligament ruptures completely, it is difficult to maintain the normal position of the clavicle once reduction has been accomplished.

Vagina-Relations-Function-Supports of the Vagina-Vaginal Examination-Prolapse of the Vagina-Vaginal Trauma

Vagina

The vagina is a muscular tube that extends upward and backward from the vulva to the uterus. It measures about 3 in. (8 cm) long and has anterior and posterior walls, which are normally in apposition. At its upper end, the anterior wall is pierced by the cervix, which projects downward and backward into the vagina. It is important to remember that the upper half of the vagina lies above the pelvic floor and the lower half lies within the perineum. The area of the vaginal lumen, which surrounds the cervix, is divided into four regions, or fornices: anterior, posterior, right lateral, and left lateral. The vaginal orifice in a virgin possesses a thin mucosal fold called the hymen, which is perforated at its center. After childbirth, the hymen usually consists only of tags

Relations

■■ Anteriorly: The vagina is closely related to the bladder above and to the urethra below.

■■ Posteriorly: The upper third of the vagina is related to the rectouterine pouch (pouch of Douglas) and its middle third to the ampulla of the rectum. The lower third is related to the perineal body, which separates it from the anal canal.

■■ Laterally: In its upper part, the vagina is related to the ureter; its middle part is related to the anterior fibers of the levator ani, as they run backward to reach the perineal body and hook around the anorectal junction. Contraction of the fibers of levator ani compresses the walls of the vagina together. In its lower part, the vagina is related to the urogenital diaphragm and the bulb of the vestibule.

 

Function

The vagina not only is the female genital canal, but it also serves as the excretory duct for the menstrual flow and

Supports of the Vagina

The upper part of the vagina is supported by the levatores ani muscles and the transverse cervical, pubocervical, and sacrocervical ligaments. These structures are attached to the vaginal wall by pelvic fascia. The middle part of the vagina is supported by the urogenital diaphragm. The lower part of the vagina, especially the posterior wall, is supported by the perineal body.

Vaginal Examination

The anatomic relations of the vagina are of great clinical importance. Many pathologic conditions occurring in the female pelvis may be diagnosed using a simple vaginal examination.

The following structures can be palpated through the vaginal walls from above downward:

■■ Anteriorly: The bladder and the urethra

■■ Posteriorly: Loops of ileum and the sigmoid colon in the rectouterine peritoneal pouch (pouch of Douglas), the rectal ampulla, and the perineal body

■■ Laterally: The ureters, the pelvic fascia and the anterior fibers of the levatores ani muscles, and the urogenital diaphragm

Prolapse of the Vagina

The vaginal vault is supported by the same structures that support the uterine cervix. Prolapse of the uterus is necessarily associated with some degree of sagging of the vaginal walls. However, if the supports of the bladder, urethra, or anterior rectal wall are damaged in childbirth, prolapse of the vaginal walls occurs, with the uterus remaining in its correct position.

Sagging of the bladder results in the bulging of the anterior wall of the vagina, a condition known as a cystocele. When the ampulla of the rectum sags against the posterior vaginal wall, the bulge is called a rectocele.

Vaginal Trauma

Coital injury, picket fence–type of impalement injury, and vaginal perforation caused by water under pressure, as occurs in water skiing, are common injuries. Lacerations of the vaginal wall involving the posterior fornix may violate the pouch of Douglas of the peritoneal cavity and cause prolapse of the small intestine into the vagina

forms part of the birth canal.