Presentation on theme: "Forearm, Wrist and Hand Anatomy Alastair Stephens Dan Waite."— Presentation transcript:
Forearm, Wrist and Hand Anatomy Alastair Stephens Dan Waite
Label the carpal bones of the wrist. Scaphoid Lunate Triquetral Pisiform Hamate Capitate Trapezoid Trapezium The blood flow can be disrupted as it runs distal to proximal and this can lead to avascular necrosis. What can a fracture of the scaphoid result in? S L T TdC Tm H P
What are the boundaries of the cubital fossa? Brachioradialis Lateral border Aponeurosis of biceps Covers roof of fossa and protects the median nerve Pronator teres Medial border Inter-epicondylar line Superior border
What are the boundaries of the anatomical snuffbox? Radial artery Radial styloid process Scaphoid Trapezium Base of 1 st metacarpal Cephalic vein passes over snuffbox EPB & AP EPL What can be palpated in the anatomical snuffbox?
What is the carpal tunnel formed by? The retinaculum attaches to pisiform, hook of hamate, scaphoid tubercle and trapezium tubercle Passes ~2cm distal to distal wrist crease P HH ST TT What passes through the carpal tunnel? Flexor digitorum superficialis (x4) Flexor digitorum profundus (x4) Flexor pollicis longus Median nerve
What are the sensory distributions of the hand? Where do you test for each nerve? Ulnar nerve on the 5 th digit Median nerve on the 2 nd digit Radial nerve over the first dorsal interosseous Ulnar Median Radial * * *
What is the innervation to these compartments? Anterior Forearm Everything is median nerve Except: Flexor carpi ulnaris (ulnar) Flexor carpi profundus to digits 4 and 5 (ulnar) Hand Everything is radial nerve Posterior Forearm Everything is ulnar nerve Except: Thenar muscles (median) Lumbrical to digits 2 and 3 (median) Median nerve Ulnar nerve Radial nerve
Radio-ulnar Joints Pronation: Median Nerve Pronator teres and pronator quadratus Supination: Musculocutaneous Nerve and Radial Nerve Biceps and Supinator Proximal radio-ulnar joint Nursemaid’s elbow Radial tuberosity Avulsion fracture by biceps Distal radio-ulnar joint What movements occur at the radio-ulnar joints?
What is Froment’s sign? Ulnar nerve damage leads to adductor pollicis brevis paralysis, leading to excess thumb flexion whilst pinching. What is Allen’s test? Allen’s test determines if there are any vascular anomalies between the radial and ulnar arteries prior to any vascular procedures. The radial and ulnar arteries are compressed and ulnar released, noting if the whole hand becomes perfused again.
What’s the difference between Ulnar Claw and Hand of Benediction? NameNerve damaged Typical presentation Digits affected Muscle Involved Ulnar Claw Ulnar nerve lesion at the wrist At restDigits 4 and 5 The lumbricals to digits 4 and 5 are paralysed. This leads to a loss of flexion at the MCP joint and a loss of extension at the IP joints. This results in the hyperextension of the MCP joints by the unopposed extensor digitorum, and the flexion of the IP joints by the unopposed flexor digitorum profundus and superficialis. Hand of Benediction Median nerve lesion at the wrist or elbow Attempting to make a fist Digits 2 and 3 The lumbricals and flexor digitorum profundus tendons to digits 2 and 3 are paralysed. This leads to a loss of flexion at the MCP joint and the DIP joints. If the patient is asked to make a fist, they will be able to flex digit 4 and 5 but not digits 2 and 3.
Steve, 72, comes to his GP complaining that he’s unable to move all of the digits on his right hand except his thumb. During the consultation, the GP notices Steve has a hoarse voice and a droopy right eyelid. What is the likely diagnosis, and explain why? Right Lung Apex Tumour (pancoast tumour) Klumpke’s Palsy Compression of the C8-T1 nerve roots leads to paralysis and wasting of the small muscles of the hand (claw hand deformity) Right recurrent laryngeal nerve compression Recurs at the right lung apex Horner’s Syndrome Compression of the cervical sympathetic chain