Answer for Anat Essay Question (5th Edition)

1. Compare and contrast between biceps and triceps muscle in details

Muscle	Biceps brachii	Triceps
Origin	Short head: tip of coracoid process Long head: supraglenoid tubercle	Long head: from infraglenoid tubercle Lateral head: back of humerus along upper lip of spiral groove Medial head:1-back of humerus below spiral groove 2-back of medial and lateral intermuscular septum
Insertion	By tendon: in posterior rough part of radial tuberosity separated from anterior smooth part by a bursa By bicipital aponeurosis: in deep fascia of upper medial side of forearm extends till posterior border of ulna	The muscle inserted by common tendon into: 1-posterior part of upper surface of olecranon process of ulna 2-fascia covering anconeus 3-a small slip from medial head inseted into back of capsule of elbow joint 4-a small bursa appears on top of olecranon process separating the tendon from back of elbow capsule
Nerve supply	Musculocutaneous neve (a branch to each head)	Radial nerve -in axilla supplies long and medial head In spiral groove supplies medial and lateral heads
Action	Powerful flexion of supinated forearm Powerful supination of flexed forearm The short head flex and adduct shoulder The long head stabilize the head of humerus opposite glenoid cavity against upper pull of deltoid	Main extensor of elbow joint Long head extends shoulder joint Long head supports lower part of capsule of shoulder joint on raising arm

2. Surface anatomy of the heart

Put the following points on anterior chest wall

Point (a): on the lower border of the 2^nd left costal cartilage 4 cm from middle line.

Point (b): on the upper border of the 3^rd right costal cartilage 3 cm from the middle line.

Point (c): on the right 6^th costal cartilage 3 cm from middle line.

Point (d): on the left 5^th intercostal space 9 cm from middle line (apex of heart).

          (1)    The upper border is a straight line between points a and b. (

          (2)    The lower border is a straight line between points c and d.

          (3)    The right border is a line slightly curved laterally between the points b and c.

          (4)    The left border is a line slightly curved laterally between points d and a.

          (5)    Atrioventricular groove its anterior part can be represented by aline between two point

a.       Point on the 3^rd left sternocostal junction.

b.      Point on the 6^th right sternocostal junction.

          (6)    Interventricular groove represented by aline from the 3^rd left sternocostal junction drawm parallel to         left border of heart till it meets inferior border.

3. Course, branches and injury of the common peroneal  nerve

Course:

It descends lateral to tibial nerve to enter popliteal fossa at its upper angle

It passes obliquely downwards and laterally in the popliteal fossa along medial border of biceps femoris

It crosses over the plantaris and lateral head of gastrocnemius

It leaves the popliteal fossa through its lateral angle.

It passes behind the head of fibula then winds forwards round its neck deep to peroneus longus 

Branches:

1- No muscular branches

2- 2 cutaneous branches

a.       Sural communicating nerve arises near the head of fibula and runs downward on lateral head of gastrocnemius to join the sural nerve

b.      Lateral cutaneous nerve of calf arises from the common peroneal nerve as it leaves the popliteal fossa. It supplies the skin of upper lateral aspect of the leg

3- 3 articular branches

a.       Superior lateral genicular runs above the lateral femoral condyle to supply the knee joint

b.      Inferior lateral genicural runs below the lateral tibial condyle to supply the knee joint

c.       Recurrent genicular arises near the end of the common peroneal nerve and ascends with the anterior tibial recurrent artery to supply knee joint and the superior tibio fibular joint

Injury:

Site and causes: wounds in the popliteal fossa or fracture of neck of fibula

Effects:

1) Motor

a.       Paralysis of the muscle of the anterior compartment of the leg as they are supplied by anterior tibial branch of lateral popliteal

b.      Paralysis of the muscle of the lateral compartment of the leg as they are supplied by the musculocutaneous branch of lateral popliteal

2) Sensory

Loss of sensation from the anterolateral aspect of the leg and the dorsum of the foot except medial and lateral borders

 3) Deformity

Foot drop due to paralysis of the extensor of foot and inversion due to paralysis of the evertors of foot. This deformity is called Talipus eqiuno varus.

BY:ASMA NASIHA BINTI MAT ARIFFIN

      SUBJEK MASTER ANATOMY 2010/2011