Cavities + Myotomes Dermatomes

Body Cavities Overview

• Cavities are hollow spaces within the body that protect and support organs and tissues.
• Key functions include providing protection, maintaining organ position, allowing movement and expansion, and separating organ systems to prevent the spread of infections.

Dorsal Body Cavity

• Located along the posterior aspect of the body.

Cranial Cavity

• Located within the skull.
• Houses the brain.

Spinal (Vertebral) Cavity

• Runs along the vertebral column.
• Contains the spinal cord.

Ventral Body Cavity

• Located along the anterior aspect of the body.
• Divided into thoracic and abdominopelvic cavities.

Thoracic Cavity

• Subdivided into three main areas:
  • Pleural Cavities: Surround each lung.
  • Pericardial Cavity: Surrounds the heart.
  • Mediastinum: Central compartment containing the heart, thymus, esophagus, trachea, and major blood vessels.

Abdominopelvic Cavity

• Contains two regions:
  • Abdominal Cavity:
    • Superior portion of the abdominopelvic cavity.
    • Contains stomach, liver, spleen, gallbladder, pancreas, small intestine, and most of the large intestine.
  • Pelvic Cavity:
    • Inferior portion of the abdominopelvic cavity.
    • Contains the urinary bladder, some reproductive organs, and the rectum.

Smaller Cavities

• Oral (Buccal) Cavity: Located in the mouth; contains teeth and tongue.
• Nasal Cavity: Located within and posterior to the nose; part of the respiratory system lined with mucous membrane.
• Orbital Cavities: Eye sockets that contain the eyes, associated muscles, nerves, and vessels.
• Middle Ear Cavities: Located in the temporal bones of the skull; contain ossicles that transmit sound vibrations.

Dermatomes

• C1: Sensation on the top of the head.
• C2: Covers the back of the head to the forehead.
• C3: Sensation from the back to the front of the neck.
• C4: Extends from the neck to the collarbone.
• C5: Includes sensation from the top of the shoulder to the wrist.
• C6: Sensation from the top of the shoulder to the tip of the pointing finger.
• C7: Covers the wrist to the middle finger.
• C8: Extends from the medial upper arm to the pinky finger.
• T1: Sensation along the forearm to the wrist.
• L1: Covers the groin area.
• L2: Sensation in the upper anterior thigh.
• L3: Covers the lower anterior thigh.
• L4: Sensation on the medial side of the lower leg.
• L5: Covers the lateral side of the lower leg and dorsum of the foot.
• S1: Sensation in the lateral aspect of the foot and heel.
• S2: Covers the posterior thigh.
• S3-S5: Sensation in the perianal area.

Myotomes

• Instructions for testing: Client must close their eyes and be seated.
• C1-C2: Neck flexion movement.
• C3: Side flexion of the neck.
• C4: Shoulder elevation movement.
• C5: Shoulder abduction movement.
• C6: Elbow flexion and wrist extension.
• C7: Elbow extension and wrist flexion.
• C8: Thumb extension and ulnar deviation.
• T1: Finger abduction movement.
• L1-L2: Hip flexion movement.
• L3: Knee extension movement.
• L4: Ankle dorsiflexion movement.
• L5: Big toe extension.
• S1: Includes ankle plantarflexion, eversion, and hip extension.
• S2: Knee flexion movement.

Reflexes

• Jaw Reflex: Evaluates Cranial Nerve 8; client opens mouth slightly, therapist taps thumb placed on chin, resulting in slight opening or closing of the mouth.
• Bicep Reflex: Involves Cranial Nerve 5; therapist locates bicep tendon, taps with thumb on the tendon to elicit reflex.
• Brachioradialis Reflex: Engages Cranial Nerve 6; therapist taps tendon near the styloid process of the radius, resulting in radial deviation.
• Triceps Reflex: Tests Cranial Nerve 7; with the arm positioned, therapist taps above the olecranon to elicit elbow extension reflex.
• Patellar Reflex (Knee-Jerk Reflex): Involves the Femoral Nerve (L2-L4); therapist taps patellar tendon while client’s legs dangle, resulting in knee extension reflex.
• Achilles Reflex (Ankle-Jerk Reflex): Engages the Tibial Nerve (S1-S2); therapist dorsiflexes the foot slightly and taps the Achilles tendon, eliciting a reflex.

Dermatomes

• C1: Sensation on the top of the head.
• C2: Covers the back of the head to the forehead.
• C3: Sensation from the back to the front of the neck.
• C4: Extends from the neck to the collarbone.
• C5: Includes sensation from the top of the shoulder to the wrist.
• C6: Sensation from the top of the shoulder to the tip of the pointing finger.
• C7: Covers the wrist to the middle finger.
• C8: Extends from the medial upper arm to the pinky finger.
• T1: Sensation along the forearm to the wrist.
• L1: Covers the groin area.
• L2: Sensation in the upper anterior thigh.
• L3: Covers the lower anterior thigh.
• L4: Sensation on the medial side of the lower leg.
• L5: Covers the lateral side of the lower leg and dorsum of the foot.
• S1: Sensation in the lateral aspect of the foot and heel.
• S2: Covers the posterior thigh.
• S3-S5: Sensation in the perianal area.

Myotomes

• Instructions for testing: Client must close their eyes and be seated.
• C1-C2: Neck flexion movement.
• C3: Side flexion of the neck.
• C4: Shoulder elevation movement.
• C5: Shoulder abduction movement.
• C6: Elbow flexion and wrist extension.
• C7: Elbow extension and wrist flexion.
• C8: Thumb extension and ulnar deviation.
• T1: Finger abduction movement.
• L1-L2: Hip flexion movement.
• L3: Knee extension movement.
• L4: Ankle dorsiflexion movement.
• L5: Big toe extension.
• S1: Includes ankle plantarflexion, eversion, and hip extension.
• S2: Knee flexion movement.

Reflexes

• Jaw Reflex: Evaluates Cranial Nerve 8; client opens mouth slightly, therapist taps thumb placed on chin, resulting in slight opening or closing of the mouth.
• Bicep Reflex: Involves Cranial Nerve 5; therapist locates bicep tendon, taps with thumb on the tendon to elicit reflex.
• Brachioradialis Reflex: Engages Cranial Nerve 6; therapist taps tendon near the styloid process of the radius, resulting in radial deviation.
• Triceps Reflex: Tests Cranial Nerve 7; with the arm positioned, therapist taps above the olecranon to elicit elbow extension reflex.
• Patellar Reflex (Knee-Jerk Reflex): Involves the Femoral Nerve (L2-L4); therapist taps patellar tendon while client’s legs dangle, resulting in knee extension reflex.
• Achilles Reflex (Ankle-Jerk Reflex): Engages the Tibial Nerve (S1-S2); therapist dorsiflexes the foot slightly and taps the Achilles tendon, eliciting a reflex.

Dermatomes

• C1: Sensation on the top of the head.
• C2: Covers the back of the head to the forehead.
• C3: Sensation from the back to the front of the neck.
• C4: Extends from the neck to the collarbone.
• C5: Includes sensation from the top of the shoulder to the wrist.
• C6: Sensation from the top of the shoulder to the tip of the pointing finger.
• C7: Covers the wrist to the middle finger.
• C8: Extends from the medial upper arm to the pinky finger.
• T1: Sensation along the forearm to the wrist.
• L1: Covers the groin area.
• L2: Sensation in the upper anterior thigh.
• L3: Covers the lower anterior thigh.
• L4: Sensation on the medial side of the lower leg.
• L5: Covers the lateral side of the lower leg and dorsum of the foot.
• S1: Sensation in the lateral aspect of the foot and heel.
• S2: Covers the posterior thigh.
• S3-S5: Sensation in the perianal area.

Myotomes

• Instructions for testing: Client must close their eyes and be seated.
• C1-C2: Neck flexion movement.
• C3: Side flexion of the neck.
• C4: Shoulder elevation movement.
• C5: Shoulder abduction movement.
• C6: Elbow flexion and wrist extension.
• C7: Elbow extension and wrist flexion.
• C8: Thumb extension and ulnar deviation.
• T1: Finger abduction movement.
• L1-L2: Hip flexion movement.
• L3: Knee extension movement.
• L4: Ankle dorsiflexion movement.
• L5: Big toe extension.
• S1: Includes ankle plantarflexion, eversion, and hip extension.
• S2: Knee flexion movement.

Reflexes

• Jaw Reflex: Evaluates Cranial Nerve 8; client opens mouth slightly, therapist taps thumb placed on chin, resulting in slight opening or closing of the mouth.
• Bicep Reflex: Involves Cranial Nerve 5; therapist locates bicep tendon, taps with thumb on the tendon to elicit reflex.
• Brachioradialis Reflex: Engages Cranial Nerve 6; therapist taps tendon near the styloid process of the radius, resulting in radial deviation.
• Triceps Reflex: Tests Cranial Nerve 7; with the arm positioned, therapist taps above the olecranon to elicit elbow extension reflex.
• Patellar Reflex (Knee-Jerk Reflex): Involves the Femoral Nerve (L2-L4); therapist taps patellar tendon while client’s legs dangle, resulting in knee extension reflex.
• Achilles Reflex (Ankle-Jerk Reflex): Engages the Tibial Nerve (S1-S2); therapist dorsiflexes the foot slightly and taps the Achilles tendon, eliciting a reflex.