Anatomy And Physiology Homework/Lab 5

synovial Synovial is a structural classification for joints. Structural classification focuses on the material binding the bones together and whether a joint cavity is present.

fibrous joint Sutures are fibrous, synarthrotic joints.

flexion Flexion is a bending movement that decreases the angle of the joint and brings the articulating bones closer together.

pronation Supination and pronation are unique to the forearm because of the arrangement of the radius and ulna. This allows rotation of our hand in space.

deep socket of the joint and strong capsular ligaments The main contributors to hip-joint stability are the deep socket of the joint and the strong capsular ligaments. Joints that have shallow sockets, such as the shoulder and jaw (temporomandibular) joints, are relatively unstable and more easily dislocated.

shoulder In the shoulder joint, stability has been sacrificed to provide the most freely moving joint in the body. The articulating bones provide minimal joint stability because of the size and "fit" of the articulating surfaces. The major stabilizing forces are soft tissue, in particular the tendons of the rotator cuff muscles (via muscle tone).

sternocleidomastoid muscles The sternocleidomastoid muscles flex and laterally rotate the head. Acting alone, each muscle rotates the head toward the shoulder on the opposite side and tilts or laterally flexes the head to the shoulder on the same side.

subscapularis; medial rotation The subscapularis originates on the subscapular fossa and inserts on the anterior surface of the head of the humerus. The lesser tubercle of the humerus is pulled toward the subscapular fossa, which leads to medial rotation.

the forearm Most of the muscles that move the hand originate in the forearm and operate the fingers via their long tendons.

shallower joint socket

adduction When the limb is moved toward the body in the coronal or frontal plane, decreasing the lateral angle of the glenohumeral joint, this is called adduction.

abduction

flexion and extension The elbow is a hinge so can only flex and extend.

pronation and supination Pronation and supination are possible in the forearm because of the joints between the radius and ulna. These are NOT movements of the elbow joint.

inversion

decreasing the angle of the knee joint by moving the leg in the posterior direction. Move the leg in the posterior direction, results in bending or flexing of the knee, decreasing the angle of the knee joint.

The toes and dorsum of the foot are pulled toward the anterior side of the body. When the muscles in the anterior compartment of the leg contract, they pull the dorsum of the foot and toes upward toward the face or ceiling. This is called extension of the toes, but there is a special name for the movement at the ankle joint: dorsiflexion of the foot. The opposite action, in which the plantar (bottom) surface of the foot and toes are pointed downward toward the floor is called plantar flexion.

The foot is turned so the plantar surface of the foot is facing laterally. When the muscles in the lateral compartment of the leg contract, they pull the bottom or the plantar surface of the foot from the lateral side so that the sole of the foot faces laterally. This is called Eversion. The opposite movement, in which the medial surface of the foo tis turned inward, is called eversion.

so that lift in leverage can be properly applied.

because it prevents the back muscle strain

lateral pterygoid. The lateral pterygoid muscle is responsible for protraction of the jaw, which results in jaw opening. It is also involved with the medial pterygoid in creating the grinding motion that occurs during chewing. The medial pterygoid, temporalis and masseter all have involvement in jaw closing or biting.

clavicular; sternocostal

medial rotation, adduction and flexion of arm.

glenohumeral joint The glenohumeral joint is the joint formed between the glenoid cavity of the scapula and the head of the humerus. The glenoid cavity is a shallow depression to accomodate the head of the humerus, but the cavity isn't deep enough to hold the head of the humerus in place. This differs from the hip joint, which has a very deep socket (the acetabulum) for the head of the femur. The glenohumeral joint (shoulder) is specialized for mobility, but lacks stability, while the hip joint is specialized for weight bearing and stability.

humeral head The distal attachments of the rotator cuff muscles form a "cuff" around the head of the humerus to help reinforce the joint.

subscapularis Subscapularis is located on the anterior surface of the scapula and insters on the anterior side of the head of the humerus (lesser tubercle).

teres major muscle

supraspinatus muscle

infrasprinatus

pectorals major The fibers of the pectoralis major muscle extend from the sternum (sternal head) and the clavicle (clavicular head) and insert on the anterior surface of the humerus. Because the pectoralis major attaches on the anterior surface of the humerus, when the muscle contracts it will pull the humerus forward in the sagittal plane (flexion), pull the humerus toward the body in the coronal plane (adduction) and medially rotate the humerus (pull the anterior surface of the humerus toward the body).

deltoid

flexion of elbow joint

subscapularis Subscapularis the rotator cuff muscles that is very difficult to see because it is located on the anterior surface of the scapula. The subscapularis muscle originates from the anterior medial border of the scapula and inserts on the anterior side of the head of the humerus. Contraction of the subscapularis will pull the anterior surface of the humerus toward the body, which is known as medial rotation of the arm.

pectoralis minor The pectoralis minor muscle attaches to the corocoid process of the scapula. When this muscle contracts, it tilts the superior part of the scapula forward and downward, resulting in depression of the scapula.

triceps brachii None of the other listed muscles cross the posterior side of the elbow joint. The triceps brachii is the predominant muscle responsible for forearm extension (extension of the elbow joint).

trapezius The trapezius can perform different actions, depending on which fibers are involved. The upper portion of the trapezius muscle can perform shoulder or scapula elevation, the lower trapezius can perform scapula depression. If both the upper and lower trapezius work together, the muscle will produce upward rotation of the scapula (as in reaching up to get something out of the cupboard).

infraspinatus and teres minor Both teres minor and infraspinatus are lateral rotators of the arm at the shoulder joint because of their attachment point on the posterior side of the head of the humerus.

This design allows the hand to maintain fine motor control and strength without the interference of bulky muscles.

deep and superficial layers

median nerve The median nerve innervates most of the muscles of the anterior compartment of the forearm, which function to flex the wrist and fingers of the hand through long tendons that extend into the hand. The median nerve and the tendons of the finger flexors travel through the carpal tunnel and can be impacted if the carpal tunnel becomes inflamed.

radial nerve The radial nerve innervates most of the muscles on the posterior side of the upper extremity. This includes the posterior compartment of the arm (triceps brachii) and the posterior compartment of the forearm (extensors of wrist and fingers). The radial nerve also innervates the brachioradialis muscle, which is an exception to the rule, since the brachioradialis is a muscle that flexes the elbow.

tendons of the flexor muscles The tendons of the long flexor muscles that control flexion of the phalanges of the fingers and thumb pass through the carpal tunnel. The median nerve also passes through the tunnel and will be impacted during carpal tunnel syndrome

inflammation of the flexor retinaculum and/or tendon sheaths

iliopsoas; femur The common insertion of the iliacus and psoas major is on the femur, and these muscles are collectively known as iliopsoas muscle.

They are powerful hip flexors. The iliopsoas muscle crosses the anterior hip joint, so flexes the hip.

Crosses anterior hip and medial knee. The satorius crosses the anterior hip and inserts on the medial tibia, so crosses the medial side of the knee joint.

flexes knee, flexes hip and laterally rotates hip The sartorius muscle flexes the knee, flexes the hip and laterally rotates the hip.

flexion of the hip Because the rectus femoris originates in the hip, and crosses the anterior hip joint, it can participate in the action of hip flexion. The rest of the quadriceps muscle group (vastus lateralis, vastus medialis and vastus intermedius) can't do this because they arise from the femur and don't cross the hip joint.

Knee

knee

ischial tuberosity of the hip bone Because the hamstring muscles originate in the pelvis, and have their insertion on the medial and lateral sides of the leg, the hamstrings can have actions at both the hip and knee joints.

extension When the quadriceps muscle group contracts, it extends the knee by pulling on the patella via the quadriceps tendon and the tibia via the patellar ligament.

femoral nerve The muscles of the anterior compartment of the thigh, and the hip flexor muscles are innervated by the femoral nerve.

adduction of the thigh (femur) at the hip joint The primary action of the muscles in the medial compartment of the thigh is adduction of the femur at the hip joint.

obturator nerve The adductor group of muscles in the medial compartment of the thigh is innervated by the obturator nerve.

hip extension and knee flexion Because the hamstrings cross both the posterior side of the hip joint and the posterior side of the knee joint, they participate in hip extension and knee flexion. Remember, the lower extremity rotated during development, so knee extension is performed by anterior thigh muscles, and knee flexion is performed by posterior thigh muscles.

sciatic nerve The sciatic nerve innervates the hamstring muscles: the semimembranosus, semitendinosus and biceps femoris.

gluteus maximus The gluteus maximus is not a hamstring muscle. It is a muscle of the posterior hip that extends the hip and can participate in lateral rotation of the hip via its connection to the iliotibial tract, or IT band. The hamstrings are the long strap-like muscles of the posterior thigh that cross both the hip joints and knee joints on the posterior sides.

an insertion for the majority of the lower leg muscles

tibialis anterior

fibularis longus

plantar flexion; gastrocnemius

flexion of the knee Because of its attachments on the distal femur, the gastrocnemius can flex the knee joint in addition to its role in plantarflexion at the ankle joint.

tibial nerve

the calcaneus via the calcaneal tendon