Directional Terms and Anatomical Orientation

Directional Terms

Directional terms are used to describe the locations of structures in relation to other structures or locations in the body.

• Proximal: Closer to the point of attachment or origin.

• Distal: Farther from the point of attachment or origin.

• Lateral: Away from the midline of the body.

• Medial: Toward the midline of the body.

• Superior/Cranial: Toward the head or upper part of a structure.

• Inferior/Caudal: Away from the head or toward the lower part of a structure.

Planes and Sutures

• Frontal/Coronal: Divides the body into anterior and posterior parts.

• Sagittal: Divides the body into right and left parts.

• Transverse: Divides the body into superior and inferior parts.

• Oblique: Passes through the body at an angle.

Body Cavities

Body cavities are spaces within the body that contain vital organs.

• Thoracic Cavity: Contains the heart and lungs.

• Abdominal Cavity: Contains digestive organs.

• Pelvic Cavity: Contains urinary bladder, reproductive organs, and rectum.

• Mediastinum: Central compartment of the thoracic cavity.

• Diaphragm: Muscle that separates the thoracic and abdominal cavities.

Bone Tissue and Structure

Types of Bone Tissue

• Compact Bone: Dense outer layer providing strength and protection.

• Spongy Bone: Porous inner layer containing red bone marrow.

Bone Anatomy

• Medullary Cavity: Central cavity of bone shafts where marrow is stored.

• Articular Cartilage: Smooth tissue covering the ends of bones at joints.

• Periosteum: Membrane covering the outer surface of bones.

• Endosteum: Membrane lining the medullary cavity.

• Epiphysis: End part of a long bone.

• Diaphysis: Shaft or central part of a long bone.

• Metaphysis/Growth Plate: Region between diaphysis and epiphysis; site of bone growth in children.

• Osteon: Structural unit of compact bone.

• Lamella: Concentric rings of bone matrix in osteons.

• Central Canal: Channel in the center of each osteon containing blood vessels and nerves.

• Collagen Fibers: Provide flexibility and tensile strength to bone.

Vertebral Column

• Cervical Vertebrae: 7 vertebrae in the neck region.

• Thoracic Vertebrae: 12 vertebrae in the upper and mid-back.

• Lumbar Vertebrae: 5 vertebrae in the lower back.

• Sacrum: 5 fused vertebrae forming the back of the pelvis.

• Coccyx: 3-5 fused vertebrae forming the tailbone.

Bones and Features of the Skull

The skull is composed of several bones and features that protect the brain and form the structure of the face.

• Frontal

• Mandible

• Maxilla

• Zygomatic

• Parietal

• Temporal

• Occipital

• Nasal

• Ethmoid

• Sphenoid

• Coronoid Process

• Styloid Process

• Mastoid Process

• External Acoustic Meatus

• Optic Canal

• Auditory Canal

• Inferior Orbital Foramen

• Superior Orbital Fissure

• Posterior Orbital Fissure

• Inferior Orbital Fissure

Spine and Vertebral Features

• Facet: Small, flat articular surface.

• Intervertebral Foramen: Openings between vertebrae for spinal nerves.

• Intervertebral Discs: Pads of cartilage between vertebrae for cushioning.

• Transverse Process: Lateral projections on vertebrae.

• Spinous Process: Posterior projection from a vertebra.

Scapula and Upper Limb Bones

• Scapula: Shoulder blade.

• Coracoid Process: Projection on the scapula for muscle attachment.

• Acromion: Outward extension of the scapula forming the highest point of the shoulder.

• Spine: Prominent ridge on the scapula.

• Glenoid Cavity: Socket in the scapula for the head of the humerus.

• Supraspinatus Fossa: Depression above the spine of the scapula.

• Infraspinatus Fossa: Depression below the spine of the scapula.

Extremities: Bones of the Arm and Leg

• Olecranon: Bony prominence of the elbow.

• Head of the Radius: Proximal end of the radius bone in the forearm.

• Fibula: Lateral bone of the lower leg.

• Tibia: Medial and larger bone of the lower leg.

• Lateral Malleolus: Distal end of the fibula (ankle).

• Medial Malleolus: Distal end of the tibia (ankle).

• Radial Process: Projection on the radius bone.

• Ulnar Process: Projection on the ulna bone.

• Radial Tuberosity: Bony prominence on the radius for muscle attachment.

• Ulnar Tuberosity: Bony prominence on the ulna for muscle attachment.

• Ilium: Uppermost and largest part of the hip bone.

• Ischium: Lower, posterior part of the hip bone.

• Pubis: Anterior part of the hip bone.

• Talus: Ankle bone that articulates with the tibia and fibula.

• Calcaneus: Heel bone.

• Metacarpals: Bones of the hand.

• Metatarsals: Bones of the foot.

Pelvis and Femur

• Symphysis Pubis: Cartilaginous joint uniting the left and right pubic bones.

• Femur: Thigh bone; the longest bone in the body.

• Femoral Neck: Narrow area just below the head of the femur.

• Greater Trochanter: Large, lateral projection on the femur for muscle attachment.

• Middle Trochanter: (Additional info: Not a standard anatomical term; possibly refers to the intertrochanteric region.)

• Lesser Trochanter: Smaller, medial projection on the femur for muscle attachment.

• Lateral Trochanter: (Additional info: Not a standard anatomical term; may refer to the greater trochanter.)

• Medial Condyle: Rounded projection at the end of the femur, articulates with the tibia.

• Lateral Condyle: Rounded projection at the end of the femur, articulates with the tibia.

Microscopy Note

• Microscope slides do not have a word bank. (Additional info: Students should be prepared to identify structures on slides without prompts.)