Understanding the Key Attachments of Fascia: An In-Depth Guide

This article aims to help other health care practitioners understand the complex interconnection of whole body fascial network in an organized manner by relating them to more conventional knowledge of human anatomy.

• Cervical investing fascia

  1. Cervical investing fascia, also known as the investing (superficial) layer of deep cervical fascia, is a layer of connective tissue in the neck that surrounds and encloses important structures. It lies just beneath the skin and superficial fascia, enveloping muscles like the sternocleidomastoid (SCM) and trapezius, and forming a protective sheath around them.

  2. It also extends to encase glands (such as the parotid and submandibular glands, the salivary glands located just in front of and below each ear) and other vital structures in the neck, acting as a protective layer that helps organize and support the tissues. This fascia is key in separating different layers and compartments within the neck.

  3. Its superior attachments include superior nuchal line (a bony ridge located on the back of the skull), mastoid process (a bony bump located just behind the ear on the lower part of the skull), external auditory tube (ear canal), masseter fascia, and distal ramus of mandible (part of the lower jaw bone). It divides at the SCM and upper trapezius while forming a sheath for each muscle group. Then it attaches to the hyoid. Then it also blend with middle cervial fascia at the medial aspect of suprahyoids. As it goes inferiorly, it has seprate attachments to anterior and posterior aspects of sternal notch. This makes a suprasternal space just superior to manubrium. The investing fascia for the submaxillary glands comes from behind the hyoid before investing the parotid gland with the masseter aponeurosis. A small ligament extends out from the lateral-anterior edge of the SCM aponeurosis. This ensures that the muscle does not compress neurovascular bundles such as carotid vessels, internal jugular vein, and the vagus nerve.

  4. The inferior attachments of cervical investing fascia include jugular notch of the sternum, manubrium, superior clavicle, and spine of scapula.

• Pre-tracheal fascia

  1. Pre-tracheal means anterior to trachea. As such, pre-tracheal fascia is situated in the anterior neck in front of trachea, thyroid gland, and esophagus, while also enclosing these structures and infrahyoid muscles. Pre-tracheal fascia can be considered to have muscular part and visceral part. Muscular part encloses infrahyoid muscles and visceral part encloses thyroid gland, trachea, and esophagus.

  2. It spans between hyoid superiorly and thorax inferiorly before blending in with the pericardium. Its attachments are hyoid, posterior clavicle, sternum, omohyoid muscles and fascia of anterior trapezius. The pretracheal fascia's attachment to the hyoid bone, as well as the thyroid and cricoid cartilages, allows the thyroid gland to move with the larynx during swallowing.

  3. Pre-tracheal fascia separates from the investing fascia at the larynx. This creates space for the jugular vein.

  4. Pre-tracheal fascia covers the SCM and omohyoid, and goes deep to cover thyrohyoid and sternohyoid muscles.

  5. Pre-tracheal fascia connects with the carotid sheath holding the common carotid, internal jugular, and vagus nerves. The internal jugular vein is held open by the tension of the carotid sheath.

  6. Below the clavicle, pre-tracheal fascia anchors and supports the brachiocephalic venous trunk and the subclavian vein. As it goes further inferior, it becomes endothoracic fascia, lining the inner surface of the thoracic cage.

  7. The posterior aspect of visceral fascia of pre-tracheal fascia is formed by the contributions from the buccopharyngeal fascia. Pharyngobasilar and buccopharyngeal fascia covers the esophagus and trachea, while running the central axis and investing the thyroid gland.

  8. From the buccinator fascia and the base of the cranium, pretracheal fascia travels inferiorly, enclosing the pericardium. It is even said to follows down to the diaphragm via pleural connection, which connects to the transversalis pertitoneum, and eventually the pelvic floor. This concept of fascial connection from neck to pelvic floor is termed "central axis".

• Pre-vertebral fascia

  1. The prevertebral fascia is a layer of deep cervical fascia located in the neck, positioned in front of the vertebral column. It envelops the vertebral column, including the cervical spine and associated muscles such as the longus colli and longus capitis muscles.

  2. Prevertebral fascia attaches to anterior longitudinal ligament and covers longus colli and scalenes.

  3. Starting at the base of the skull, the prevertebral fascia extends laterally, connecting to the fascia of the levator scapulae, the nuchal fascia, and the superficial fascia of the neck, while also enclosing the brachial plexus and the subclavian artery.

  4. Prevertebral fascia also extends down to the endothoracic fascia while providing many extensions that stabilize the pleural domes.

• Endothoracic fascia

  1. Deep cervical fascia continues inferiorly to form endothoracic fascia. Endothoracic fascia continues inferiorly to form transversalis fascia after a detour to create the diaphragm. Endothoracic fascia is dense and ropey so that it can provide suspension as it envelopes the pleural dome. As it superiorly transitions into the deep cervical fascia, it envelops scalenes.

  2. The endothoracic fascia is a thin layer of connective tissue that lines the inside of the thoracic (chest) cavity. It lies between the inner surface of the ribs and the parietal pleura, which is the outer layer of the membrane that surrounds the lungs. The endothoracic fascia acts as a protective layer, helping to attach the parietal pleura to the thoracic wall, diaphragm, and structures in the mediastinum (the central compartment of the chest). It also provides a pathway for blood vessels and nerves to pass through and supports the overall structure of the thoracic cavity.

  3. Outer layer of endothoracic fascia attaches to the inner surface of the thoracic cavity. Inner layer of endothoracic fascia attaches to the pleura and pericardium. Inferiorly, endothoracic fascia attaches to the diaphragm and transversalis fascia.

• Transversalis fascia

  1. Transversalis fascia is continuation of endothoracic fascia.

  2. The transversalis fascia lines the inner surface of the abdominal wall and is closely attached to the parietal peritoneum via the fascia propria, making it difficult to differentiate the two.

  3. In its lower part, the fascia splits to form a protective sac around the kidney. This sac is created by the retrorenal fascia, which is attached posteriorly to the major blood vessels and the vertebrae, and the prerenal fascia. These two layers merge on the sides in front to form the sac enclosing the kidneys.

  4. The upper portion of the fascia attaches to the diaphragm, while the lower portion connects to the iliac fascia. The lower section comes into contact with the organs of the pelvic region and is continuous with the parietal peritoneum. It has an extension to form the inguinal canal, forming the fibrous sheath of the spermatic cord. It also has an extension to envelop the external iliac arteries.

  5. The transversalis fascia blends with the linea alba.

• Lateral raphe

  1. The lateral raphe is a fibrous structure found in the lower back region, formed by the blending of the aponeuroses (fibrous connective tissue sheets) of several muscles. It acts as a point of attachment and support for these muscles and plays a key role in stabilizing the lower back and maintaining the integrity of the abdominal wall. In also helps transmit forces between the abdominal and back muscles, contributing to core stability and movement.

  2. Lateral raphe is located lateral to the erecter spinae and superior to iliac crest. It is formed by the middle layer and posterior layer of the thoracolumbar fascia. This is where the transversus abdominis and internal oblique muscles attach together. This point also creates the lumbar interfascial triangle (LIFT), which defines the separation of anterior and posterior spine. LIFT is an important anatomical structure for proper load distribution from muscles and fascia of torso to the lower extremity while maintaining the stability of the pelvis and spine.

Reference

Paoletti, S. (2006). The Fasciae—Anatomy, dysfunction, and treatment (English Edition). Eastland press.