Question

. Be able to identify the following muscles of arms and legs, Also know their origin, insertion and
movement caused by them
A. Deltoid, Biceps brachii, Brachialis and other major muscles of arm.
B. Sartorius, Rectus femoris, Vastus medialis and Vastus lateralis muscle, Gluteus maximus

Answer 1

Muscles of arms:

Deltoid - Deltoid is a rounded, triangular muscle located at the shoulder and arm joint. The deltoid is attached by tendons to the skeleton at the clavicle (collarbone), scapula (shoulder blade), and humerus (upper arm bone). The deltoid muscle is responsible for a precise and rapid movement of the glenohumeral joint needed for hand and arm manipulation. The deltoid muscle is involved in the movement of elevating the arm in the scapular plane and its contraction in doing this also elevates the humeral head.

Biceps brachii - The biceps brachii is a two-headed muscle that lies on the upper arm between the shoulder and the elbow. Both heads arise on the scapula and join to form a single muscle belly which is attached to the upper forearm. Its main movement is at the elbow where it flexes the forearm and supinates the forearm.

Brachialis - The brachialis is a muscle in the upper arm that flexes the elbow joint. It lies deeper in than the biceps brachii.The mai movement of brachialis is elbow flexion.

Triceps brachii - Triceps means three headed in latin is a large muscle in the back of upper limb of the arm and is about double the size of biceps brachii. Its main movement is extension of elbow joint for straightening of the arm.

Muscles of legs:

Sartorius - Sartorius is the longest muscle in the human body. It is a long, thin, superficial muscle that runs down the length of the thigh in the anterior compartment. The sartorius muscle can move the hip joint and the knee joint. At the hip, this muscle can flex, weakly abduct, and laterally rotate the thigh. At the knee, it can flex the leg; when the knee is flexed, sartorius medially rotates the leg. It is evident from the description of the movement and body parts involved that this is the longest muscle in human body.

Rectus femoris - Rectus femoris muscle is situated in the middle of the front thigh. Its main movements are to flex the thigh at the hip joint and to extend the leg at the knee joint.

Vastus medialis - The vastus medialis is an extensor muscle located medially in the thigh that extends the knee. This muscle along with other muscles are responsible for knee extension.

Vastus laterialis - Vastus laterialis is a strongest and longest part of quadriceps femoris muscle of thigh. Its main movement is to work with other muscles for forward movement of lower leg.

Gluteus maximus - The Gluteus maximus is the main extensor muscle of the hip. It decides the shape and appearance of the hip. Its main action is to cause the body to regain the erect position after stooping, by drawing the pelvis backward. This is done in assistance with other muscles.