The ulnar nerve is formed from the medial cord nerve roots of C7-T1. Originating in the brachial plexus, it descends down the arm before passing around the medial epicondyle of the elbow (the so-called funny bone) and then passes between the heads of flexor carpi ulnaris (FCU). It gives some cutaneous branches just before the wrist whilst the motor branches pass around the hook of hamate. Its motor contribution is to all small muscles of the hand except the lateral two lumbricals as well as FCU and flexor digitorum profundus (FDP). Its sensory supply is to the one and a half ulna side fingers
The foramen ovale is part of the greater wing of the sphenoid and transmits the mandibular and lesser petrosal nerve. This nerve enters the infratemporal fossa through the petrotympanic fissure and runs downward and forward to join the lingual nerve. The foramen spinosum transmits the middle meningeal artery from the infratemporal fossa into the cranial cavity. The jugular foramen transmits the following structures from before backward: inferior petrosal sinus, CN IX, X, XI, and the large sigmoid sinus. The facial nerve exits the cranium via the stylomastoid foramen.
Hyponatraemia can be classified as a hypovolaemic, euvolaemic or hypervolaemic state. Hypovolaemic state is due to marked dehydration with excessive salt losses, for example, vomiting or Addison's disease. Euvolaemic state typically reflects syndrome of inappropriate secretion of antidiuretic hormone (SIADH). Hypervolaemic state is due to conditions such as congestive cardiac failure (CCF), cirrhosis, nephrotic syndrome and myxoedema. Carbenoxolone causes pseudohyperaldosteronism with hypertension, hypernatraemia and hypokalaemia. Major surgery, pneumonia, subarachnoid, meningitis and injury (as well as drugs) can induce SIADH.
* Radioscaphoid joint
* Scapholunate joint
* Scaphocapitate joint
* Scaphotrapezial joint
* Scaphotrapezoidal joint
Muscle attachments: Abductor pollicis brevis
Ligament attachments: None
Fractures: Scaphoid fracture
Tubercle is blunt prominence to thumb side of distal surface. Waist of the bone is palpable in anatomical snuff box.
The posterior cricoarytenoids are the (only) cord abductors. They are innervated by the recurrent laryngeal nerve.
Femoral hernias lie in the femoral canal which is the medial compartment of the femoral sheath, the opening to which is the femoral ring. The femoral canal contains lymphatics, and therefore causes of enlarged lymph nodes form part of the differential diagnosis (that is, lymphoma, infection). However, Virchow's node (Troisier's sign) is a supraclavicular lymph node, associated with intra-abdominal malignancy (that is, gastric) and does not form part of the differential. The intermediate compartment of the sheath contains the femoral veins and therefore a saphena varix may be mistaken for a hernia due to the close proximity. The femoral artery lies in the lateral compartment. The walls of the sheath are formed by a continuation of the fascia transversalis interiorly and posterior iliacus/psoas fascia. A psoas abscess will therefore track along the fascia, under the ligament into the groin, lying in a similar position to a femoral hernia.
The dermatomes for C8, T1 and T2 lie along the medial border of the upper limb, with the medial part of the forearm being supplied by T1. The muscles of the hand are supplied by either the ulnar (C8-T1) or the median nerve (C5-T1), with the hypothenar eminence being supplied solely by the ulnar nerve. The superficial palmar arch is a direct continuation of the ulnar artery and lies lateral to the hook of hamate. As the artery enters the palm it curves laterally behind the palmar aponeurosis and superficial to the flexor tendons. The trapezium articulates (via a synovial saddle-shaped joint) with the base of the first metacarpal to form the carpometacarpal joint of the thumb.
The median nerve...
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