Bio 107 Lab: Muscles

The Epicranius Frontal Body, also known as the frontalis muscle, covers the frontal bone of the skull and is responsible for raising the eyebrows and wrinkling the forehead.

The Epicranius muscle is actually composed of two separate muscles, the Frontalis muscle and the Occipitalis muscle. The Frontalis muscle is often referred to as the 'Epicranius'.

The Orbicularis Oculi is a muscle that closes the eyelids. It is not to be confused with the Trapezius, Rectus Abdominis, or Deltoid muscles which have different functions in the body.

Orbicularis Oris is the muscle responsible for controlling the movements of the mouth and lips, while Masseter, Temporalis, and Buccinator are muscles involved in mastication and facial expression.

The mentalis muscle is responsible for the movement of the lower lip and wrinkling of the chin.

The buccinator muscle is primarily responsible for compressing the cheeks inward to keep food between the teeth and aid in actions like blowing or sucking.

The Masseter muscle is responsible for the movement of the jaw, specifically closing it. Its origin is the Zygomatic Arch and Maxilla, while its insertion is the Angle and Ramus of the Mandible.

The Platysma muscle is specifically located in the neck region and is responsible for movements related to the jaw and lip, not other body parts like the elbow or eye.

The zygomaticus muscle, specifically the zygomaticus major and zygomaticus minor, are the primary muscles responsible for smiling by pulling the corners of the mouth upwards.

The risorius muscle is a facial muscle that contributes to expressions such as smiling, as it pulls the corners of the mouth sideways.

The Sternocleidomastoid muscle originates from the manubrium of the Sternum and medial portion of the clavicle, inserts into the mastoid process of the temporal bone and the superior nuchal line of the occipital bone, and functions to flex the neck and rotate the head toward the shoulder on the opposite side.

The Pectoralis Major muscle originates from the clavicle, sternum, and cartilage of ribs 1-6, inserts into the intertubicular sulcus of the humerus, and is responsible for arm flexion, medial adduction, and arm rotation.

The deltoid muscle originates from the lateral 1/3 of the clavicle, acromion, and spine of the scapula, inserts into the deltoid tuberosity on the Humerus, and is the prime mover of arm abduction.

The Pectoralis Minor muscle has a specific origin, insertion, and action that are different from the incorrect answers provided. It is important to understand the correct anatomical details to properly identify the muscle.

The Rectus Abdominis is commonly referred to as the 'abs' muscle and is responsible for flexing the spine and providing stability during activities like standing and sitting.

The correct answer is the External Oblique muscle, which is located on the sides and front of the abdomen and aids in lateral flexion and rotation of the trunk. Rectus Abdominis is responsible for spinal flexion, Gluteus Maximus is the largest muscle of the buttocks and aids in hip extension, and Deltoid is a muscle responsible for shoulder movement.

The Internal Oblique is one of the muscles of the abdominal wall that plays a role in trunk rotation and spine flexion. The External Oblique is also a muscle on the side of the abdomen but is responsible for different movements. Rectus Abdominis is the muscle that forms the infamous 'six-pack' and is primarily responsible for flexing the spine. Transversus Abdominis is another muscle of the abdominal wall that aids in core stability.

The transverse abdominis is a deep muscle that wraps around the abdomen and plays a key role in stabilizing the core and maintaining good posture. Rectus abdominis is commonly known as the 'six-pack' muscle, oblique abdominis refers to the external and internal obliques, and psoas major is a muscle located in the lower back that plays a role in hip flexion.