Hand Musculature and Vasculature, Cross sections, Review Upper Extremity Hand Musculature and Vasculature, Cross sections, Review

Presentation Wrist Biomechanics

Objectives Describe the gross anatomy for each system (circulatory, muscular, nervous, and skeletal) in the upper extremity. Integrate the systems to discuss the upper extremity stability and mobility functions. Analyze common injuries in the upper extremities. For each muscle, describe how the attachment sites result in an action around a joint. For each muscle, identify the innervation (peripheral nerve and nerve roots). Pulled from syllabus

The brachioradialis: has a tendon that passes deep to the flexor retinaculum. attaches to the medial epicondyle of the humerus. is innervated by the radial nerve. acts at both the elbow and wrist joints. extends the elbow. C

posterior interosseous anterior interosseous You are assisting in the emergency room when the attending physician examines a patient after an elbow injury. The physician holds the proximal interphalangeal joint of the little finger and asks the patient to flex the distal phalanx. This procedure tests the functionality of what nerve? radial ulnar median posterior interosseous anterior interosseous B

Elbow tendonitis (tennis elbow) is associated with: inflammation of the periosteum of the lateral epicondyle of the humerus. inflammation of the medial collateral ligament. inflammation of the annular ligament. rupture of the tendon of the extensor digitorum. transient subluxation of the humero-radial-ulnar joint. A

Forearm vascular supply radial and ulnar arteries interosseous arteries primarily from ulnar, also receive blood from radial (yay functional anastomoses!!) Superior and inferior collateral arteries

Review thumb actions stress opposition (no mcp joints)

Fascia Protective anoneurosis Essential for palms to protect deep neurovasculature -> hands used for everything!!! Not nearly as strong as…. Dog paws for example Palmaris brevis

Muscle groups, spaces

No distal hand cross sections in VH – but know the carpal tunnel and the extensor tunnels in cross section!!

Infections tend to follow and fill synovial sheaths -> little finger will be infected if midpalmar space becomes infected. Tendons in the palm: FPL, FDP, FDS (9 total)

Interossei and lumbricals 3 palmar, 4 dorsal No lumbrical attachments???

Lumbricals – 1&2 unipennate, 3&4 bipennate Innervations? Pad and dab

Synovial sheaths and fibrous digital sheath Tendons well protected, but not from knife grabbing

Avascular necrosis or scaphoid fracture without necrosis can lead to arthritis down the road treatment focuses on treating symptoms of arthritis – splint, anti-inflammatories, etc. surgery if treatment is ineffective 3 arches to know – also know which arteries contribute to each superficial palmar – radial and ulnar deep palmar – same, with anterior interosseous dorsal carpal – both interosseous arteries, radial

Thenar muscles Hypothenar muscles Adductor pollicis two heads Deep palmar arch

Neurovasculature in relation to muscles (superficial palmar arch, ulnar and median nerve branches) Ulnar canal compression of ulnar nerve in the hand

Posterior cutaneous nerve of forearm from radial n. Distribution on hand

Medial cutaneous nerve mislabeled

Clinical Relevance Dupuytren Contracture Tenosynovitis Carpal Tunnel Syndrome Dupuytren Contracture disease of palmar fascia thickening, shortening, fibrosis contracts digits 4&5 surgery to cut palmar aponeurosis Tenosynovitis inflammation of the tendon and synovial sheat 2nd-4th digits usually confined to the digit, 5th digit often spreads to common sheath & carpal tunnel tenovaginitis stenosans -> fibrous thickening of sheath and stenosis of osseofibrous tunnel (stenosis = narrowing of a passage; tenovaginitis = tenosynovitis)

Clinical Relevance Carpal Tunnel Syndrome Ulnar Nerve Injury Radial Nerve Injury Raynaud’s disease Carpal Tunnel syndrome any lesion or swelling that increases pressure within the carpal tunnel median nerve compression paresthesia (tingling), hypesthesia (reduced sensation), anesthesia (loss of sensation) in median nerve distribution central palm remains unaffected because palmar cutaneous branch does not go through carpal tunnel weakness of 3 thenar muscles thenar eminence may emaciate, opposition weak Ulnar nerve injury 1. post to medial epicondyle 2. cubital tunnel between two heads of FDP 3. at the wrist 4. in the hand 1-3 difficulty flexing wrist (unbalanced – weak FCU), difficulty making a fist (instrinsic deep muscles weakened), difficulty extending IP joints of digits (lumbricals weak): claw hand 4 ulnar canal syndrome (deep to pisohamate ligament) – weakness of instrinsic muscles only Radial Nerve Injury wrist drop (previously discussed) Raynaud’s Disease cold or emotional stimulus -> cyanosis of digits, pain/paresthesia sympathetic nervous system out of control constriction of distal arteries (temperature regulating mechanism gone haywire)

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Which of the following is incorrect pertaining to the clavicle? It is attached via ligaments to the coracoid process. After a fracture, the medial segment is raised by the sternocleidomastoid muscle. Fractures are almost always accompanied by acromioclavicular dislocation. Patients with fractured clavicles typically need to support the ipsilateral upper limb with the contralateral one. D

flexor digitorum superficialis abductor pollicis longus The ridge indicated by the arrow in the following photograph overlies the tendon of which of the following muscles? palmaris longus palmaris brevis flexor carpi radialis flexor digitorum superficialis abductor pollicis longus C

Which of the following statements is incorrect pertaining to the extensors carpi radialis longus and brevis muscles? When only the two muscles act together, wrist extension and abduction is produced. When the two muscles act with the extensor carpi ulnaris, only wrist extension is produced. When the two muscles act with the flexor carpi ulnaris, only wrist abduction is produced. One of the muscles is innervated by the ulnar and the other by the deep branch of the radial nerve. Both attach to the humerus. D

fractured distal radius (Colles fracture). mid-radial fracture. In the emergency room you see a 65-year-old woman who fell on her outstretched right hand while walking on ice. Upon examination of the right limb, you feel and see a dorsal protrusion just proximal to the wrist. You suspect a: fractured lunate. fractured distal radius (Colles fracture). mid-radial fracture. dislocated first carpometacarpal joint. dislocated midcarpal joint. B

Following an avulsion fracture of the greater tubercle of the humerus, the humerus would primarily be: laterally rotated. medially rotated. abducted. flexed. extended. B

short head of biceps tendon basilic vein In the following axial MRI through the distal third of the arm, the brachial artery is labeled number 1 (see thin leader line on image). What is the structure indicated by the arrow? ulnar artery radial nerve cephalic vein short head of biceps tendon basilic vein C

The cephalic vein: becomes the brachial vein. becomes the axillary vein. originates on the medial side of the dorsal venous network at the wrist. pierces the clavipectoral fascia. empties into the subclavian vein. D

You examine a young male patient whose shoulder was injured during a football game. You immediately notice that his acromion process is abnormally prominent and inferior to the acromial end of the clavicle. You suspect: an anteriorly dislocated glenohumeral joint. a posteriorly dislocated glenohumeral joint. a dislocated acromioclavicular joint with intact coracoclavicular ligaments. a dislocated acromioclavicular joint with torn coracoclavicular ligaments. a torn rotator cuff. D

Scapulohumeral rhythm refers to: the changing articular configuration of the humeral head in the glenoid cavity with movement. the protective contractions of the rotator cuff muscles with humeral abduction. the protractive and retractive movements of the scapula that occur with humeral flexion and extension. the association between the movements at the glenohumeral and acromioclavicular joints. the relationship between movements at the glenohumeral and scapulothoracic "joints" during humeral abduction. E

Which of the following relationships at the wrist is incorrect? The median nerve lies deep to the tendon of the palmaris longus. The ulnar artery and nerve lie lateral to the tendon of the flexor carpi ulnaris. The radial artery can be compressed against the radius. The radial artery lies medial to the tendon of the flexor carpi radialis. The scaphoid can be palpated in the floor of the anatomical snuffbox. D

Which of the following is incorrect pertaining to carpal tunnel syndrome? It may involve weakness in the thenar muscles. It may involve anesthesia of the central palm. It may involve paresthesia in the lateral 3½ digits. It may be caused by inflammation of the synovial sheaths of the flexor tendons. Surgical transection of the flexor retinaculum typically relieves its associated symptoms. B

Enter Question Text Enter Answer Text

Upper arm

Lower arm

Cubital fossa

Upper forearm

Middle forearm

Objectives Describe the gross anatomy for each system (circulatory, muscular, nervous, and skeletal) in the upper extremity. Integrate the systems to discuss the upper extremity stability and mobility functions. Analyze common injuries in the upper extremities. For each muscle, describe how the attachment sites result in an action around a joint. For each muscle, identify the innervation (peripheral nerve and nerve roots). Pulled from syllabus

Wednesday Neck Due Monday: step 1 of open topic essay (rough draft!!) Readings Due Monday: step 1 of open topic essay (rough draft!!)